Two-Position Snap Caps for 17 mm PP Test Tubes — LDPE, Natural, 1000/Bag (300-3817-02P)
These Caplugs® Evergreen two-position snap caps are designed specifically for 17 mm polypropylene test tubes, offering a practical dual-function closure for microbiology, cell culture, and sample storage workflows. Molded from low-density polyethylene (LDPE) in a natural (translucent) color, each cap snaps into a partial-open position for gas exchange during incubation and into a fully closed position for sealed refrigerated or frozen storage — and remains attached to the tube in both positions so there is never a loose cap to set down or misplace. Supplied non-sterile in 1000/Bag, part number 300-3817-02P is the PP-tube variant of the 300-3817 series.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3817-02P |
| Cap Style | Two-Position Snap Cap |
| Tube Format | 17 mm PP Test Tubes |
| 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): partial-open position maintains CO₂ and O₂ exchange during incubation in 17 mm culture tubes
- Cell culture and virus propagation in 17 mm tubes: partial-open for gas exchange during incubation, fully closed for transport between runs
- Sealed refrigerated or frozen storage: fully closed position prevents evaporation and contamination during hold periods between workflow steps
- Clinical chemistry and environmental sampling: closed snap seals large-format 17 mm sample tubes during transport and pre-analysis staging
- Sequential open/close cycling workflows: the cap remains attached in both positions, eliminating the risk of losing or contaminating a loose cap on the bench
Compatibility
These snap caps are dimensioned to fit 17 mm polypropylene test tubes. Labs working with 17 mm polystyrene tubes should select the companion variant, part number 300-3817-02S, which provides the same two-position function for the PS tube format. Facilities that use smaller 12 mm PP culture tubes will find the identical two-position snap functionality in the 300-3812-02P, which is scaled to that narrower tube diameter. Because fit tolerances can vary across tube manufacturers and lots, Caplugs® Evergreen recommends validating the snap engagement 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 frozen temperatures |
Quality & Procurement
Made in USA, these Caplugs® Evergreen snap caps are manufactured from BPA-free, phthalate-free LDPE resin. The inherent flexibility of LDPE is precisely what enables reliable snap-position engagement cycle after cycle, while also maintaining inertness to standard culture media and aqueous reagents. LabSupplies.com is an authorized Caplugs® Evergreen dealer and ships from USA inventory, with tiered volume pricing available for clinical labs, hospitals, research institutions, and biotech procurement teams purchasing in case quantities.
Frequently Asked Questions
What is the difference between Position 1 and Position 2?
Position 1 is a partial-open, vented position that allows CO₂ and O₂ gas exchange — ideal for microbiology and cell culture incubation. Position 2 is fully closed, creating a sealed closure suitable for refrigerated or frozen storage and sample transport. The cap stays attached to the tube in both positions.
Will these caps fit 17 mm polystyrene tubes?
No — these caps (300-3817-02P) are dimensioned for 17 mm polypropylene tubes. For 17 mm polystyrene tubes, select the companion variant 300-3817-02S, which provides the same two-position snap function for that tube format.
Can these caps be autoclaved?
No. LDPE softens at autoclave temperatures (121 °C) and is not suitable for steam sterilization. For workflows requiring sterile closures, consider pre-sterilizing tubes and caps by alternative methods, or contact our team to discuss sterile-format options.
How do these compare to the 300-3812-02P caps?
The 300-3812-02P delivers the same two-position snap functionality — partial-open venting and fully closed sealing — but is sized for 12 mm PP test tubes rather than the larger 17 mm format. Both caps share the same LDPE material and natural color; the difference is tube diameter.