MST™ Flat Top Cryogenic Vial Caps — HDPE, Black, 200/Bag (300-3910-FZ20)
These black HDPE flat-top cryogenic vial caps from the Caplugs® Evergreen MST™ line are engineered for long-term biospecimen storage at temperatures ranging from –80°C ULT freezers down to –196°C liquid nitrogen vapor phase and full immersion. Opaque black HDPE provides complete blockage of visible and UV light, making these caps the right choice whenever maximum light exclusion is required for photosensitive specimens. Part number 300-3910-FZ20 is the twelfth and final color completing the MST™ flat-top cap family, supplied 200 caps per bag.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3910-FZ20 |
| Sub-brand | MST™ (Caplugs® Evergreen) |
| Cap Profile | Flat Top |
| Material | High-Density Polyethylene (HDPE) |
| Color | Black |
| Light Blockage | Complete — opaque black HDPE absorbs all visible and UV light |
| Cryogenic Rating | LN₂ vapor phase and immersion (–196°C) |
| ULT Storage | –80°C compatible |
| Autoclave Compatible | Yes — 121°C / 15 psi |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Pack Size | 200/Bag |
| Country of Origin | USA (California) |
Applications
- Long-term biobank archiving in LN₂ vapor phase at –196°C, where HDPE maintains full structural integrity
- ULT –80°C biorepository storage of serum, plasma, tissue, and nucleic acid specimens
- Light-sensitive specimen cryopreservation — bilirubin, porphyrins, therapeutic drug monitoring (TDM) analytes, and other photodegradable samples requiring complete light exclusion
- Cell line cryopreservation in DMSO-based cryoprotectant media, where HDPE offers good compatibility at standard 5–10% DMSO concentrations
- Any workflow where complete opaque light blockage is required and partial attenuation (as with amber caps) is insufficient
Compatibility
MST™ caps are designed exclusively for MST™ cryogenic vials and are not interchangeable with CryoSure® vials or other vial platforms. Within the MST™ system, Caplugs® Evergreen offers three distinct cap profiles: Flat Top (300-3910 series, 12 colors), Recessed Top (300-3914 series), and Tethered Recessed (300-3918 series). Choose the cap profile that matches your MST™ vial format and workflow ergonomics. When light protection is needed but some visual inspection of vial contents is still required, the MST™ Amber flat-top cap (300-3910-FN20) provides partial light attenuation while remaining translucent; for complete light exclusion, these black caps (300-3910-FZ20) are the appropriate choice.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Liquid nitrogen, –196°C (vapor phase and immersion) | Excellent — engineered for LN₂ service |
| ULT storage at –80°C | Excellent — HDPE cryo-toughened |
| Aqueous cryoprotectants / buffers | Excellent |
| DMSO at standard cryo concentrations (5–10%) | Good — suitable for routine cryopreservation media |
| Autoclave (121°C / 15 psi) | Compatible |
| Concentrated organic solvents | Not recommended |
Quality & Procurement
Made in USA at Caplugs® Evergreen's California facility, these MST™ vial caps are produced from BPA-free, phthalate-free HDPE resin under ISO 9001 quality management. LabSupplies.com is an authorized Caplugs® Evergreen dealer stocking MST™ consumables and shipping from USA inventory, with tiered pricing available for institutional purchasers, biobanks, and grant-funded research programs.
Frequently Asked Questions
How do these black caps differ from the MST™ amber flat-top caps?
The amber MST™ cap (300-3910-FN20) is translucent and provides only partial attenuation of visible light, which can be useful when technicians need to visually inspect vial contents. The black cap delivers complete light blockage of all visible and UV wavelengths, making it the correct choice for photosensitive specimens such as bilirubin or porphyrins where any light exposure risks analyte degradation.
Are these caps compatible with liquid nitrogen immersion, or only vapor phase?
MST™ HDPE flat-top caps are rated for both LN₂ vapor phase and full immersion storage at –196°C, as well as ULT –80°C freezer use. HDPE is specifically selected for its cryogenic toughness across this temperature range.
Can I autoclave these caps before use?
Yes — the HDPE construction is autoclave-compatible at standard 121°C / 15 psi cycles, making pre-use sterilization straightforward for sterile workflow applications.
Will these caps fit my existing CryoSure® vials?
No. MST™ caps are engineered specifically for MST™ vials and are not interchangeable with CryoSure® vials or other vial formats. Confirm that your vials are from the MST™ platform before ordering.