MST™ Recessed-Top Cryogenic Vial Caps — HDPE, Blue, 200/Bag (300-3914-HB20)
These blue High-Density Polyethylene recessed-top cryogenic vial caps from the Caplugs® Evergreen MST™ line are engineered for long-term sample archiving in liquid nitrogen vapor phase and immersion storage down to -196°C, as well as standard -80°C ultra-low temperature freezers. The recessed-top profile sets the cap's upper surface below the outer rim of the cap body, shielding it from contact damage inside cryo boxes and during routine vial handling. Supplied as 200 caps per bag, part number 300-3914-HB20 represents the most economical profile in the MST™ cap range.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3914-HB20 |
| Sub-brand | MST™ (Caplugs® Evergreen) |
| Cap Profile | Recessed Top — top surface set below outer rim |
| Material | High-Density Polyethylene (HDPE) |
| Color | Blue |
| Cryo Rating | LN₂ vapor phase and immersion (-196°C) |
| ULT Freezer Compatibility | -80°C |
| Autoclave Compatibility | 121°C / 15 psi |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Pack Size | 200/Bag |
| Country of Origin | USA (California) |
Applications
- Long-term LN₂ vapor-phase and immersion biobanking of clinical and research samples archived in MST™ recessed-top cryogenic vials
- -80°C ultra-low temperature biorepository storage, where HDPE cryo-toughened construction maintains a reliable seal across freeze-thaw cycles
- Color-coded sample routing workflows using the three available recessed-top colors (Natural, Blue, Yellow) to align with CLSI or laboratory-defined conventions — blue mirrors the CLSI H3 blue-top citrate convention for easy visual identification
- Cryopreservation of cell lines in DMSO-containing media, where HDPE provides good compatibility with standard 5–10% cryoprotectant concentrations
- Cost-optimized high-throughput cryo-capping programs where the recessed-top profile offers the lowest per-cap cost in the MST™ line
Compatibility
These caps are designed exclusively for MST™ recessed-top cryogenic vials and are not interchangeable with CryoSure® vials or flat-top MST™ vials. Unlike the Tethered Recessed MST™ cap (300-3918), which remains attached to the vial after opening via a flexible tether, the recessed-top cap in this format removes completely from the vial — making it well suited for workflows where full cap removal is preferred. Laboratories already using the flat-top MST™ cap (300-3910) should note that both caps share the same MST™ vial thread but have a different top profile; confirm your vial type before switching.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Liquid nitrogen (-196°C) — vapor and immersion | Excellent — engineered for LN₂ service |
| Storage at -80°C | Excellent — HDPE cryo-toughened |
| Aqueous cryoprotectants | Excellent |
| DMSO (5–10% standard cryo media) | Good — short-term contact at standard cryo concentrations |
| Autoclave (121°C / 15 psi) | Compatible |
| Concentrated organic solvents | Not recommended |
Quality & Procurement
Made in USA at Caplugs® Evergreen's California facility, these MST™ caps are produced from BPA-free, phthalate-free HDPE resin engineered to maintain structural integrity across the full temperature range from autoclave sterilization (+121°C) through liquid nitrogen immersion (-196°C). LabSupplies.com is an authorized Caplugs® Evergreen dealer and ships from USA inventory, with tiered volume pricing available for biobanks, clinical laboratories, and research institutions managing large-scale cryopreservation programs.
Frequently Asked Questions
What makes the recessed-top profile different from a flat-top MST™ cap?
The recessed-top design sets the cap's upper surface below the outer rim of the cap body, so the top is protected from contact abrasion when vials are stacked or handled in cryo boxes. The flat-top cap (300-3910) has a flush upper surface and a different top profile, though both fit the same MST™ vial thread.
Are these caps compatible with CryoSure® cryogenic vials?
No. MST™ caps, including 300-3914-HB20, are designed exclusively for MST™ cryogenic vials and are not interchangeable with CryoSure® vials. Always confirm your vial brand before ordering replacement caps.
Can these caps be autoclaved before use?
Yes. The HDPE construction is compatible with standard autoclave cycles at 121°C and 15 psi, supporting sterile-field workflows or re-sterilization protocols.
Are recessed-top MST™ caps available in other colors?
Only three colors are offered in the recessed-top format: Natural, Blue, and Yellow. If your workflow requires a different color, consider the flat-top or tethered MST™ cap profiles, which may offer additional color options.