20 mL Vial & 30 mL Centrifuge Tube Screw Caps — HDPE, Red, 1000/Bag (300-3532-R20)
These red High-Density Polyethylene (HDPE) screw caps from Caplugs® Evergreen are designed to fit 20 mL screw-neck vials and 30 mL centrifuge tubes, supplied non-sterile in convenient 1000/Bag quantities for high-throughput clinical and research workflows. The red color follows the widely recognized CLSI H3 red-top serum/no-additive tube convention, making these caps immediately identifiable for serum-containing large-format tubes in clinical chemistry, immunoassay, and serology settings. HDPE construction delivers leak-free IATA P650-compliant closure, -80°C cryogenic stability for biorepository programs, and autoclave compatibility at 121°C.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3532-R20 |
| Cap Type | Screw cap — threaded engagement |
| Material | High-Density Polyethylene (HDPE) |
| Color | Red |
| Tube Compatibility | Caplugs® Evergreen 20 mL screw-neck vials and 30 mL centrifuge tubes |
| Thread Note | Larger thread than 300-3010/300-3022 — not interchangeable |
| IATA P650 | Compliant — leak-free primary container seal |
| Cryogenic Storage | Compatible to -80°C |
| Autoclave Compatibility | Compatible (121°C / 15 psi) |
| Sterility | Non-Sterile |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Pack Size | 1000/Bag |
| Country of Origin | USA (California) |
Applications
- Capping 20 mL screw-neck vials in clinical chemistry, immunoassay, and serology workflows where the red color designates serum/no-additive specimens per CLSI H3 convention
- Securing 30 mL centrifuge tubes during centrifugation — the threaded engagement retains the cap through centrifuge forces
- Biorepository archiving of 20 mL and 30 mL frozen specimens at -80°C, supported by HDPE cryo stability
- IATA P650-compliant leak-free closure for compliant transport of primary biological specimens
- Color-coded batch routing in multi-specimen processing environments, leveraging the universal clinical recognition of the red-top convention
- Replacement cap supply for existing Caplugs® Evergreen 20 mL vial and 30 mL centrifuge tube inventory
Compatibility
These caps are engineered for the Caplugs® Evergreen 20 mL screw-neck vial and 30 mL centrifuge tube families. Procurement managers should note that the 300-3532 series uses a larger thread specification than the 300-3010 and 300-3022 cap families used with 15 mL tubes — the two thread sizes are not interchangeable. Before placing a bulk order, validate cap-to-tube thread fit with a sample to confirm compatibility with your current tube stock.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / saline | Excellent |
| Dilute acids and bases | Good |
| Alcohols (ethanol, isopropanol) | Good — short-term contact |
| Many organic solvents (general) | Good |
| Chlorinated / aromatic solvents | Not recommended — test before use |
| Cryogenic storage (to -80°C) | Compatible |
| Autoclaving (121°C / 15 psi) | Compatible |
Quality & Procurement
Made in USA at Caplugs® Evergreen's California manufacturing facility, these HDPE screw caps are produced from BPA-free, phthalate-free resin under ISO 9001 quality management. LabSupplies.com is an authorized Caplugs® Evergreen dealer shipping from USA inventory, with tiered volume pricing available for clinical labs, hospitals, biorepositories, and research institutions purchasing at scale.
Frequently Asked Questions
Will these caps fit my existing 15 mL centrifuge tubes?
No. The 300-3532 series uses a larger thread specification designed for 20 mL screw-neck vials and 30 mL centrifuge tubes. The 300-3010 and 300-3022 families serve the 15 mL tube format and are not interchangeable with these caps. Always validate thread fit with a sample before committing to a bulk order.
Are these caps suitable for frozen biorepository storage?
Yes. HDPE maintains its dimensional stability and sealing integrity down to -80°C, making part number 300-3532-R20 appropriate for long-term frozen archiving of serum, plasma, and other biological specimens in 20 mL and 30 mL tube formats.
Are these caps compliant for shipping biological specimens?
Yes. These screw caps provide an IATA P650-compliant leak-free closure, meeting the primary container sealing requirements for compliant transport of biological specimens.
Why choose red caps specifically?
Red mirrors the CLSI H3 red-top serum/no-additive tube convention — the most universally recognized clinical tube color for serum-containing specimens in clinical chemistry, immunoassay, and serology. Using red caps on large-format 20 mL and 30 mL tubes extends that familiar color vocabulary to high-volume specimen workflows, reducing sorting errors without additional staff retraining. If your laboratory uses a different color-routing system, the 300-3532 range is available in multiple additional solid colors with an identical HDPE thread specification.