{"product_id":"caplugs-300-2912-r20-ldpe-test-tube-stopper-12mm-red","title":"Test Tube Stoppers, LDPE, Red, BD® Compatible — 300-2912-R20 | 1000\/Bag | Caplugs® Evergreen","description":"\u003ch2\u003e12 mm Test Tube Stoppers — LDPE, Red, BD® Vacutainer-Compatible | 1000\/Bag (300-2912-R20)\u003c\/h2\u003e\n\u003cp\u003eThese red LDPE plug-in stopper caps fit standard 12 mm OD test tubes — including 12 × 75 mm and 12 × 100 mm glass and polystyrene culture tubes as well as BD® Vacutainer-compatible collection tube formats — and are supplied non-sterile in 1000\/Bag for high-volume laboratory capping programs. The red color mirrors the CLSI H3 red-top serum tube convention, making these stoppers an intuitive fit for clinical chemistry, immunoassay, and serology workflows that route specimens by tube color. Low-density polyethylene construction provides the flex modulus necessary for reliable friction-fit retention across repeated insertion and removal cycles without fracture.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number (MPN)\u003c\/td\u003e\n\u003ctd\u003e300-2912-R20\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube OD\u003c\/td\u003e\n\u003ctd\u003e12 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCap Style\u003c\/td\u003e\n\u003ctd\u003eStopper — plug-in friction fit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eLow-Density Polyethylene (LDPE)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColor\u003c\/td\u003e\n\u003ctd\u003eRed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColor Convention\u003c\/td\u003e\n\u003ctd\u003eCLSI H3 red-top serum tube standard\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Tube Formats\u003c\/td\u003e\n\u003ctd\u003e12 × 75 mm and 12 × 100 mm glass and PS culture tubes; BD® Vacutainer-compatible sizes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Range\u003c\/td\u003e\n\u003ctd\u003e-20°C to +60°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSterility\u003c\/td\u003e\n\u003ctd\u003eNon-Sterile\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePack Size\u003c\/td\u003e\n\u003ctd\u003e1000\/Bag\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBPA \/ Phthalates\u003c\/td\u003e\n\u003ctd\u003eBPA-free; no phthalate plasticizers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCountry of Origin\u003c\/td\u003e\n\u003ctd\u003eUSA (California)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eApplications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eClinical chemistry \u0026amp; serology specimen archiving:\u003c\/strong\u003e Red stoppers follow the CLSI H3 convention for serum tubes, making color-coded specimen routing straightforward across clinical chemistry, immunoassay, and serology benches.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMicrobiology culture tube capping:\u003c\/strong\u003e LDPE flexibility maintains a reliable seal on TSB, BHI, LB broth, and other culture media tubes throughout 37°C incubation cycles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRefrigerated and frozen storage:\u003c\/strong\u003e Flexibility is retained at -20°C, enabling clean insertion and removal during frozen archive access without stopper fracture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCell culture and virus propagation:\u003c\/strong\u003e Stopper-style closure on 12 mm suspension culture tubes prevents contamination while permitting controlled gas exchange.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePneumatic tube transport:\u003c\/strong\u003e LDPE friction retention withstands the acceleration forces of clinical pneumatic transport systems, keeping sample tubes securely closed in transit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePre-analysis sample tube closure:\u003c\/strong\u003e Suitable for sealing serum, plasma, and urine tubes prior to and during analyzer loading in clinical laboratory workflows.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCompatibility\u003c\/h2\u003e\n\u003cp\u003eThe 300-2912-R20 stopper is designed to fit the 12 mm OD tube diameter used by BD® Vacutainer® collection tubes and the standard 12 × 75 mm and 12 × 100 mm glass and polystyrene culture tube formats common across clinical and research laboratories. The 12 mm diameter represents the broadest compatibility range in the Caplugs® Evergreen stopper series, covering the tube sizes most frequently used in clinical chemistry, microbiology, and hematology specimen programs. Laboratories currently using OEM red stoppers with BD® or equivalent 12 mm tube systems can transition to these stoppers as a direct plug-in replacement; verify the OD of your specific tube lot before committing to large-volume orders.\u003c\/p\u003e\n\n\u003ch2\u003eChemical Resistance\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eReagent \/ Condition\u003c\/th\u003e\n\u003cth\u003eCompatibility\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAqueous buffers, saline, water\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSerum, plasma, urine, whole blood\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMicrobiology broth media (TSB, BHI, LB)\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDilute acids and bases\u003c\/td\u003e\n\u003ctd\u003eGood\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEthanol and alcohols\u003c\/td\u003e\n\u003ctd\u003eGood — short-term contact\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAcetone \/ chlorinated solvents\u003c\/td\u003e\n\u003ctd\u003eNot recommended\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAromatic solvents (toluene, xylene)\u003c\/td\u003e\n\u003ctd\u003eNot recommended\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eQuality \u0026amp; Procurement\u003c\/h2\u003e\n\u003cp\u003eMade in USA (California), these Caplugs® Evergreen stoppers are produced from BPA-free, phthalate-free LDPE resin under ISO 9001 quality management, ensuring consistent dimensional tolerances and material purity across every bag. LabSupplies.com is an authorized Caplugs® Evergreen dealer shipping from USA inventory, with same-business-day dispatch available for stocking items and volume pricing tiers available for institutional, hospital, and grant-funded procurement programs.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these stoppers sterile?\u003c\/strong\u003e\u003cbr\u003eNo — they are supplied non-sterile in 1000\/Bag packaging. For sterile applications such as aseptic cell culture or virus propagation, surface-sterilize stoppers before use according to your facility's SOP.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWill these stoppers fit BD® Vacutainer® tubes?\u003c\/strong\u003e\u003cbr\u003eYes — BD® Vacutainer® collection tubes use a 12 mm OD format, and these stoppers are designed to fit standard 12 mm OD tubes. Verify the OD of your specific tube lot before large-volume deployment, as minor dimensional variation can exist between manufacturers.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan these stoppers be used at freezer temperatures for archived samples?\u003c\/strong\u003e\u003cbr\u003eYes — LDPE retains its flexibility at -20°C, so the stoppers can be inserted and removed from frozen archive tubes without becoming brittle or cracking. The rated temperature range is -20°C to +60°C.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhy red? Does the color indicate anything specific?\u003c\/strong\u003e\u003cbr\u003eRed follows the CLSI H3 convention for serum collection tubes, the most widely recognized clinical tube color designation. Using red stoppers on 12 mm serum specimen tubes allows laboratory staff to route and identify specimens by color without additional labeling, reducing handling errors in high-throughput clinical workflows.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\/\",\"@type\":\"Product\",\"name\":\"12 mm Test Tube Stoppers, LDPE, Red, BD® Vacutainer-Compatible — 1000\/Bag\",\"sku\":\"300-2912-R20\",\"mpn\":\"300-2912-R20\",\"brand\":{\"@type\":\"Brand\",\"name\":\"Caplugs® Evergreen\"},\"material\":\"Low-Density Polyethylene (LDPE)\",\"color\":\"Red\",\"offers\":{\"@type\":\"Offer\",\"priceCurrency\":\"USD\",\"price\":\"44.13\",\"availability\":\"https:\/\/schema.org\/InStock\"}}\u003c\/script\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\/\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"Are these stoppers sterile?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No — they are supplied non-sterile in 1000\/Bag packaging. For sterile applications such as aseptic cell culture or virus propagation, surface-sterilize stoppers before use according to your facility's SOP.\"}},{\"@type\":\"Question\",\"name\":\"Will these stoppers fit BD® Vacutainer® tubes?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes — BD® Vacutainer® collection tubes use a 12 mm OD format, and these stoppers are designed to fit standard 12 mm OD tubes. Verify the OD of your specific tube lot before large-volume deployment, as minor dimensional variation can exist between manufacturers.\"}},{\"@type\":\"Question\",\"name\":\"Can these stoppers be used at freezer temperatures for archived samples?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes — LDPE retains its flexibility at -20°C, so the stoppers can be inserted and removed from frozen archive tubes without becoming brittle or cracking. The rated temperature range is -20°C to +60°C.\"}},{\"@type\":\"Question\",\"name\":\"Why red? Does the color indicate anything specific?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Red follows the CLSI H3 convention for serum collection tubes, the most widely recognized clinical tube color designation. Using red stoppers on 12 mm serum specimen tubes allows laboratory staff to route and identify specimens by color without additional labeling, reducing handling errors in high-throughput clinical workflows.\"}}]}\u003c\/script\u003e","brand":"Caplugs® Evergreen","offers":[{"title":"Default Title","offer_id":48567097786600,"sku":"300-2912-R20","price":44.13,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0694\/5361\/1240\/files\/300-2912-R20_01.jpg?v=1779031863","url":"https:\/\/labsupplies.com\/products\/caplugs-300-2912-r20-ldpe-test-tube-stopper-12mm-red","provider":"LabSupplies.com","version":"1.0","type":"link"}