12 mm Test Tube Stoppers — LDPE, Yellow, BD® Compatible | 1000/Bag (300-2912-Y20)
These yellow LDPE plug-in friction-fit stoppers are engineered for 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. Supplied non-sterile in 1000/Bag quantities, they are sized for the most widely used tube diameter in clinical and research settings. The yellow color follows the CLSI H3 convention for SPS (Sodium Polyanethol Sulfonate) blood culture tubes and ACD (Acid Citrate Dextrose) tube designation, making these stoppers a natural fit for color-coded specimen routing in microbiology and hematology workflows.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-2912-Y20 |
| Tube OD | 12 mm |
| Compatible Tube Formats | 12 × 75 mm and 12 × 100 mm glass and PS culture tubes |
| Cap Style | Stopper — plug-in friction fit |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Yellow |
| Color Convention | SPS blood culture / ACD tube designation (CLSI H3) |
| Temperature Range | -20°C to +60°C |
| Sterility | Non-Sterile |
| Pack Size | 1000/Bag |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Country of Origin | USA |
Applications
- Microbiology culture tube capping — seals TSB, BHI, LB broth, and blood culture tubes during incubation; LDPE flexibility is maintained at 37°C
- Specimen tube archiving — prevents evaporation and contamination of serum, plasma, and urine samples during refrigerated or frozen (-20°C) storage
- Clinical color-coded tube routing — yellow stoppers follow the CLSI H3 convention for SPS and ACD tubes, enabling accurate specimen-type identification without relabeling
- Cell culture capping — suitable for suspension culture and virus propagation tubes where a flexible stopper closure is required
- Pneumatic tube transport — LDPE flex retention helps maintain seal integrity during clinical sample transport through pneumatic systems
Compatibility
These stoppers are compatible with standard 12 mm OD test tubes across glass and polystyrene formats, including BD Vacutainer®-compatible collection tubes and common polypropylene clinical tube formats in the 12 × 75 mm and 12 × 100 mm sizes. The 12 mm diameter represents the broadest compatibility range in the Caplugs® Evergreen stopper series, making part number 300-2912-Y20 the appropriate choice for laboratories that cap high volumes of general clinical chemistry, microbiology culture, and hematology specimen tubes. Always confirm the outer diameter of your specific tube before ordering to ensure a proper friction-fit seal.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / saline | Excellent |
| Serum, plasma, urine | Excellent |
| Broth media (TSB, BHI, LB) | Excellent |
| Dilute acids and bases | Good |
| Alcohols (short-term contact) | Good |
| Chlorinated solvents (chloroform, DCM) | Not recommended |
| Aromatic solvents (toluene, xylene) | Not recommended |
| Autoclaving | Not recommended |
Quality & Procurement
Made in USA, these Caplugs® Evergreen stoppers are manufactured from BPA-free, phthalate-free LDPE resin under ISO quality management standards. The low flex modulus of LDPE is specifically selected for stopper-style closures, providing consistent friction retention across repeated insertion and removal cycles without cracking, and maintaining seal engagement across the rated temperature range from frozen archive conditions to incubator temperatures. LabSupplies.com is an authorized dealer of Caplugs® Evergreen consumables and ships from USA inventory, with tiered volume pricing available for high-throughput clinical labs, hospitals, and research institutions.
Frequently Asked Questions
Are these stoppers sterile?
No — they are supplied non-sterile in 1000/Bag packaging. For applications requiring sterile closures, additional decontamination steps should be validated by your laboratory.
What tube types are these compatible with?
These stoppers 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. Confirm your tube's outer diameter is 12 mm before use, as slight dimensional variation between manufacturers can affect friction-fit retention.
Why are these stoppers yellow?
Yellow corresponds to the CLSI H3 color convention for SPS (Sodium Polyanethol Sulfonate) blood culture tubes and ACD (Acid Citrate Dextrose) tubes. Using yellow stoppers in a color-coded routing system allows staff to identify specimen types quickly and accurately without additional labeling.
Can these stoppers be used for frozen specimen storage?
Yes — the LDPE material retains flexibility down to -20°C, so the stopper can be removed and reinserted without cracking during frozen archive access, a common limitation of more rigid cap materials.