Two-Position Snap Caps for 17 mm PS Test Tubes — LDPE, Natural, 1000/Bag (300-3817-02S)
These Caplugs® Evergreen LDPE snap caps are engineered for 17 mm polystyrene test tubes and offer two distinct positions in a single, always-attached cap: a partial-open position that allows CO₂ and O₂ gas exchange during incubation, and a fully closed position that seals the tube for refrigerated storage or transport. Supplied non-sterile in 1000/Bag, they bring the proven two-position snap functionality of the 12 mm series (300-3812-02S) to the larger 17 mm culture tube format, eliminating the loose-cap problem that invites contamination and workflow interruptions at the bench.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3817-02S |
| Tube Format | 17 mm PS test tubes |
| Cap Style | Two-position snap cap |
| Position 1 | Partial-open — gas exchange / venting |
| Position 2 | Fully closed — sealed for storage and transport |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Natural |
| Sterility | Non-Sterile |
| Pack Size | 1000/Bag |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Country of Origin | USA |
Applications
- Microbiology broth culture (TSB, BHI, LB) in 17 mm culture tubes — partial-open position maintains culture atmosphere during incubation
- Cell culture and virus propagation in 17 mm tubes — partial-open for CO₂ exchange, fully closed for transport between steps
- Sealed refrigerated or frozen storage between incubation runs — fully closed position prevents evaporation and contamination
- Clinical chemistry large-format sample tubes — closed position prevents evaporation prior to analysis
- Environmental field collection in 17 mm tubes — closed snap for transport, partial-open for on-site sampling
- Any workflow requiring repeated open/close cycling — the cap remains attached in both positions, eliminating loose caps at the bench
Compatibility
Part number 300-3817-02S is dimensioned specifically for 17 mm polystyrene (PS) test tubes. Laboratories working with 17 mm polypropylene (PP) tubes should select the companion variant 300-3817-02P, which provides the same two-position snap function in the PP tube format. For smaller 12 mm PS culture tubes, the 300-3812-02S offers identical two-position snap functionality scaled to that diameter. Because tube wall thickness and rim geometry can vary by manufacturer, it is advisable to validate snap fit with your specific tube brand before committing to a bulk purchase.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers and culture media | Excellent |
| Dilute acids (<10%) | Good |
| Short-chain alcohols (brief contact) | Good |
| DMSO (≤10%) | Good |
| Autoclave (121 °C) | Not compatible — LDPE softens at autoclave temperatures |
| Storage at −20 °C | Suitable — LDPE retains flexibility at low temperatures |
Quality & Procurement
Made in USA, these Caplugs® Evergreen snap caps are manufactured from BPA-free, phthalate-free LDPE resin selected for the flexibility required to engage and disengage the two-position snap mechanism reliably over repeated use cycles. LabSupplies.com is an authorized Caplugs® Evergreen dealer, shipping from USA inventory with tiered pricing available for institutional, clinical, and grant-funded laboratories placing volume orders.
Frequently Asked Questions
What is the difference between the two positions on these snap caps?
Position 1 is a partial-open, vented position that allows gas exchange — ideal for aerobic or CO₂-dependent culture incubation. Position 2 is fully closed, creating a sealed environment appropriate for refrigerated or frozen storage, centrifugation prep, or transport. The cap remains attached to the tube in both positions.
Will these caps fit 17 mm PP test tubes as well?
No — this cap is dimensioned for 17 mm PS tubes. For 17 mm PP tubes, select the companion variant 300-3817-02P. Tube wall geometry differs between PS and PP, so using the correct variant ensures a reliable snap fit.
Can these LDPE caps be autoclaved?
No. LDPE softens at autoclave temperatures (121 °C) and is not suitable for steam sterilization. These caps are supplied non-sterile and are intended for workflows that do not require terminal sterilization of the cap itself.
How do these caps compare to the 300-3812-02S?
The 300-3812-02S provides the same two-position snap functionality but is sized for 12 mm PS test tubes. This cap scales that design to the larger 17 mm PS format. Both are LDPE, natural color, non-sterile, and packed 1000/Bag.