20 mL Vial & 30 mL Centrifuge Tube Screw Caps — HDPE, Purple, 1000/Bag (300-3532-U20)
These purple High-Density Polyethylene (HDPE) screw caps are engineered to fit Caplugs® Evergreen 20 mL screw-neck vials and 30 mL centrifuge tubes, delivering a leak-free threaded closure that meets IATA P650 transport requirements. Supplied non-sterile in bags of 1000, they support -80°C biorepository storage and autoclave sterilization at 121°C, making them versatile across clinical, research, and biobank workflows. The purple color adds a distinct routing dimension for labs where standard CLSI convention colors are already allocated to primary tube categories.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3532-U20 |
| Cap Type | Screw cap — threaded engagement |
| Material | High-Density Polyethylene (HDPE) |
| Color | Purple |
| Tube Compatibility | Caplugs® Evergreen 20 mL screw-neck vials; 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 |
| Pack Size | 1000/Bag |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Country of Origin | USA (California) |
Applications
- Capping Caplugs® Evergreen 20 mL screw-neck vials for primary specimen collection and transport
- Securing 30 mL centrifuge tubes through centrifugation cycles — threaded engagement retains the cap under centrifuge forces
- Color-coded batch routing in clinical labs where primary CLSI convention colors are already assigned; purple designates specialized sub-type batches, overflow accession categories, or specific anatomic site collections
- Biorepository archiving of 20 mL and 30 mL frozen specimens at -80°C
- IATA P650 compliant leak-free closure for regulated transport of infectious or diagnostic specimens
- Replacement cap supply for existing Caplugs® Evergreen 20 mL vial and 30 mL centrifuge tube inventory
Compatibility
These caps are designed exclusively for the Caplugs® Evergreen 20 mL screw-neck vial and 30 mL centrifuge tube families. 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. Validate cap-to-tube thread fit with a sample quantity before placing a bulk order, particularly when transitioning from an existing cap supplier or consolidating tube formats. Purple is one of 14 solid colors available in the 300-3532 range; all share the identical HDPE thread specification, so color is the only variable between SKUs in this family.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers and saline | Excellent |
| Dilute acids and bases | Excellent |
| Alcohols (ethanol, isopropanol) | Good |
| Many organic solvents | Good — verify with concentrated or prolonged exposure |
| Chlorinated solvents (chloroform, DCM) | Limited — not recommended for long-term contact |
| Aromatic solvents (toluene, xylene) | Limited — not recommended for long-term contact |
| Cryogenic storage (-80°C) | Compatible |
| Autoclave (121°C / 15 psi) | Compatible |
Quality & Procurement
Made in USA (California), these Caplugs® Evergreen screw caps are manufactured from BPA-free, phthalate-free HDPE resin under ISO 9001 quality management standards. LabSupplies.com is an authorized Caplugs® Evergreen dealer, shipping from USA inventory with same-business-day fulfillment available on stocking items. Tiered volume pricing is available for high-throughput clinical laboratories, hospital systems, biobanks, and grant-funded research programs — contact our team for institutional and blanket-order arrangements.
Frequently Asked Questions
Will these caps fit my existing 15 mL centrifuge tubes?
No. The 300-3532 series uses a larger thread specification than the 300-3010 and 300-3022 families, which are sized for 15 mL tubes. The two thread sizes are not interchangeable — confirm your tube format before ordering.
Are these caps autoclavable?
Yes. The HDPE construction is compatible with standard autoclave cycles at 121°C / 15 psi, making them suitable for workflows that require sterilized closures.
Can these caps be used for frozen biorepository storage?
Yes. HDPE maintains its structural integrity and thread seal down to -80°C, making part number 300-3532-U20 appropriate for long-term cryogenic archiving of specimens in 20 mL vials and 30 mL centrifuge tubes.
Why choose purple over other available colors in this cap family?
Purple provides an additional color dimension in labs where the more common CLSI convention colors — such as red, green, yellow, and lavender — are already assigned to primary tube categories. It is commonly used for specialized sub-type batches, overflow accession groups, or site-specific collection programs, enabling visual differentiation at a glance without relabeling tubes.