Caplugs® Evergreen
Test Tube Stoppers, LDPE, Yellow, BD® Compatible — 300-2912-Y20 | 1000/Bag | Caplugs® Evergreen
Test Tube Stoppers, LDPE, Yellow, BD® Compatible — 300-2912-Y20 | 1000/Bag | Caplugs® Evergreen
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Test Tube Stopper Caps for 12 mm Test Tubes, LDPE, Yellow — 300-2912-Y20 | 1000/Bag
| Quick Reference — 300-2912-Y20 | |
|---|---|
| Tube OD | 12 mm |
| Cap Type | Stopper (plug-in friction fit) |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Yellow |
| Color Convention | Yellow stoppers correspond to the SPS (Sodium Polyanethol Sulfona |
| Tube Types | Standard 12 × 75 mm, 12 × 100 mm glass and PS culture tubes |
| Sterility | Non-Sterile |
| Pack Size | 1000 / Bag |
| Price | $44.13 / Bag ($0.0442 / stopper) |
Technical Narrative
The Caplugs® Evergreen is a yellow LDPE stopper cap for 12 mm OD test tubes — the most widely used diameter in general laboratory and clinical tube formats. 12 mm covers standard 12 × 75 mm and 12 × 100 mm glass and PS culture tubes, BD Vacutainer-compatible collection tube sizes, and the most common polypropylene clinical test tube formats. Yellow stoppers correspond to the SPS (Sodium Polyanethol Sulfonate) blood culture tube convention in the CLSI H3 system, and are also used for ACD (Acid Citrate Dextrose) tube designation — making yellow the natural stopper color for blood culture tube closure and microbiology specimen batches in color-coded routing systems.
The 12 mm size represents the broadest compatibility range in the Caplugs® Evergreen stopper series — it is the format most laboratories require in the largest volumes for clinical chemistry, microbiology culture, and hematology specimen tube workflows. LDPE construction provides the flex modulus required for stopper-style friction retention across repeated insertion/removal cycles without fracture, while maintaining flexibility at -20°C for frozen archive tube access and retaining seal engagement at 37°C incubation temperature. LDPE chemical inertness to serum, plasma, urine, and broth media ensures no cap leaching into tube contents during storage.
At $44.13 per 1000/Bag — $0.0442 per stopper — the delivers yellow 12 mm stopper coverage at per-stopper economics for high-volume tube capping programs. The complete 12 mm color range is available — see the table below to select the color matching your laboratory's tube routing protocol.
Technical Specifications — Caplugs® Evergreen
| Specification | Value |
|---|---|
| Part Number | |
| Caplugs Item # | 3002912Y20E1 |
| Tube OD | 12 mm |
| Cap Style | Stopper — plug-in friction fit |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Yellow |
| Color Convention | Yellow stoppers correspond to the SPS (Sodium Polyanethol Sulfonate) blood cultu |
| Tube Compat. | Standard 12 × 75 mm and 12 × 100 mm glass and PS culture tubes |
| Temp. Range | -20°C to +60°C |
| Sterility | Non-Sterile |
| Pack Size | 1000 / Bag |
| BPA/Phthalate | BPA-free; no phthalate plasticizers |
| Country of Origin | Made in U.S.A. (California) |
Test Tube Stopper Application Compatibility —
The yellow 12 mm LDPE stopper fits standard 12 mm OD test tubes for the following workflows:
| Application | Tube / Specimen Type | Notes |
|---|---|---|
| Culture tube capping | Microbiology culture tubes, TSB, BHI, LB broth | LDPE stopper seals tube during incubation; flex retained at 37°C |
| Specimen tube archiving | Serum, plasma, urine in refrigerated/frozen storage | Prevents evaporation during extended cold storage |
| Clinical tube color routing | 12 mm OD clinical tubes in color-coded systems | CLSI-convention color stoppers for specimen-type routing |
| Cell culture capping | Suspension culture, virus propagation | Stopper allows gas exchange while preventing contamination |
| Pneumatic tube transport | Sample tube transport in clinical tube systems | LDPE flex retention survives transport acceleration forces |
| Chemistry tube sealing | Pre-analysis sample tube closure | LDPE inert to serum/plasma; no leaching into specimen |
| Hematology specimen capping | EDTA blood tubes (lavender), CBC prep tubes | Lavender stoppers for EDTA-tube closure; white for barcode-labeled CBC |
| Research tube closure | Buffer, reagent, stock solution tube archiving | Stopper seals reusable glass and PS tubes between uses |
Always validate stopper fit with your specific tube brand before bulk purchase — 12 mm OD tubes vary in opening diameter by wall thickness. Request a free sample to confirm friction-fit retention.
Chemical Resistance — Low-Density Polyethylene (LDPE)
LDPE provides the flexibility essential for stopper-format tube caps and broad chemical inertness to clinical specimen matrices.
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / water | ✓ Excellent |
| Urine / serum / plasma | ✓ Excellent |
| Cell culture media | ✓ Excellent |
| Dilute acids (<10%) | ✓ Good |
| Dilute alkalies (pH <12) | ✓ Good |
| Short-chain alcohols (brief) | ✓ Good |
| DMSO (≤10%) | ✓ Good — brief contact |
| Concentrated organic solvents | ✗ Not recommended |
| Autoclave (121°C) | ✗ Not compatible |
| Storage at -20°C | ✓ Suitable — LDPE retains flexibility |
Complete 12 mm Stopper Color Range — Caplugs® Evergreen
All 12 mm LDPE stopper colors are identical in material and friction-fit performance. Color selection is protocol-driven:
| Part Number | Color | Price/1000 | Primary Convention / Use |
|---|---|---|---|
| 300-2912-B20 | Blue | $44.13 | Citrate anticoagulant / blue-top convention |
| 300-2912-E20 | Orange | $44.13 | STAT / priority specimen designation |
| 300-2912-G20 | Green | $44.13 | General specimen-type or batch routing |
| 300-2912-K20 | Fuchsia | $44.13 | GYN / gynecologic specimen designation |
| 300-2912-L20 | Lavender | $44.13 | EDTA anticoagulant / lavender-top convention |
| 300-2912-R20 | Red | $44.13 | Serum / red-top convention |
| 300-2912-W20 | White | $44.13 | Universal default / label-based ID |
| Yellow | $44.13 | SPS culture / special tube designation |
Laboratory Applications
The serves clinical and research microbiology programs capping culture tubes; clinical chemistry and hematology labs using CLSI-convention color-coded stopper routing; anatomic pathology programs designating specimen-type batches with color stoppers; cell culture programs capping tubes during incubation; and any laboratory requiring high-volume friction-fit closure on 12 mm OD test tubes.
U.S. Manufacturing, Quality & Institutional Procurement
Every Caplugs® Evergreen lot is precision-molded at our California manufacturing facility and subject to rigorous dimensional inspection and material purity verification. We supply reference laboratories, hospital systems, and federal procurement offices under institutional pricing programs with blanket-order support and same-day shipping. Request a free sample below to validate stopper fit with your tube brand before committing to volume.
Frequently Asked Questions — Caplugs® Evergreen
What is the clinical color convention for yellow 12 mm tube stoppers?
Yellow stoppers correspond to the SPS (Sodium Polyanethol Sulfonate) blood culture tube convention in the CLSI H3 system, and are also used for ACD (Acid Citrate Dextrose) tube designation — making yellow the natural stopper color for blood culture tube closure and microbiology specimen batches in color-coded routing systems. The Caplugs® Evergreen 12 mm stopper range covers all 8 CLSI H3 tube-top color conventions and general-purpose colors — see the complete color table above for the full range.
Which CLSI H3 tube-top conventions does the 12 mm stopper range cover?
The Caplugs® Evergreen 12 mm stopper range covers the primary CLSI H3 vacuum tube color conventions: Red (300-2912-R20): serum/no additive; Lavender (300-2912-L20): EDTA anticoagulant (CBC, HbA1c, molecular); Blue (300-2912-B20): sodium citrate anticoagulant (coagulation); Yellow : SPS/ACD (blood culture, HLA); Green (300-2912-G20): heparin (plasma, stat chemistry); Orange (300-2912-E20): STAT/thrombin activation; White (300-2912-W20): universal/barcode-labeled; Fuchsia (300-2912-K20): GYN/anatomic pathology designation. All eight are available at $44.13/1000. Select colors based on your laboratory's specific tube routing protocol.
Why is LDPE used for stopper caps rather than PP or PS?
Stopper-style caps work by friction fit — the plug must compress under insertion and spring back against the tube wall to retain. PP and PS are too rigid and crack under repeated insertion/removal cycles. LDPE's low-density flex modulus allows thousands of stopper cycles without fracture, retains flexibility at -20°C to prevent brittle failure during frozen archive access, and provides chemical inertness to clinical specimen matrices.
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