Two-Position Snap Caps for 12 mm PP Test Tubes — LDPE, Natural, 1000/Bag (300-3812-02P)
These Caplugs® Evergreen LDPE snap caps are designed specifically for 12 mm polypropylene test tubes and offer two distinct functional positions without ever leaving the tube: a partial-open first snap that allows CO₂ and O₂ gas exchange during incubation, and a fully closed second snap that seals the tube for storage and transport. Supplied non-sterile in 1000/Bag, part number 300-3812-02P is the PP-tube variant and is manufactured from low-density polyethylene to provide the flex required for reliable snap engagement through repeated open/close cycling in demanding microbiology and clinical workflows.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-3812-02P |
| Tube Format | 12 mm PP 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 culture tube capping: The partial-open position allows aerobic or microaerophilic gas exchange during broth culture incubation (TSB, BHI, LB) while keeping the tube protected from environmental contamination.
- Sealed storage and archiving: The fully closed position provides a contamination-free seal for refrigerated or frozen tube storage between workflow steps.
- Clinical chemistry pre-analytical hold: The closed snap position prevents evaporation and contamination during staging of sample tubes ahead of analysis.
- Cell culture and virus propagation: Partial-open position supports gas exchange in suspension culture and viral propagation tubes; closed position protects samples during transport.
- Environmental and field sampling: Tubes can be snapped closed for field transport, then moved to the partial-open position at point of use — all without removing or misplacing the cap.
- High-frequency open/close cycling: The LDPE two-position mechanism allows tubes to be accessed repeatedly throughout a workflow without cap degradation or the risk of setting down and losing a loose stopper.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / saline | Excellent |
| Dilute acids and bases | Good |
| Alcohols (ethanol, isopropanol) | Good — short-term contact |
| Many aqueous organics and biological media | Good |
| Chlorinated solvents (chloroform, DCM) | Not recommended |
| Aromatic solvents (toluene, xylene) | Not recommended |
| Autoclaving | Not recommended for LDPE |
Quality & Procurement
Made in USA, these Caplugs® Evergreen snap caps are manufactured from BPA-free, phthalate-free LDPE resin. LabSupplies.com is an authorized dealer of Caplugs® Evergreen laboratory consumables and ships from USA inventory, with tiered pricing available for high-volume institutional, clinical, and research purchasing. Note that the PS-tube variant — for 12 mm polystyrene test tubes — is a separate item; confirm your tube substrate before ordering to ensure proper cap fit.
Frequently Asked Questions
What is the difference between the partial-open and fully closed positions?
The first snap holds the cap ajar, creating a vent gap that allows CO₂ and O₂ gas exchange — ideal for aerobic or microaerophilic culture incubation. The second snap seats the cap fully against the tube rim for a sealed closure used during refrigerated storage, freezing, or transport.
Does the cap stay on the tube in both positions?
Yes — that is the key workflow advantage of this design. The cap remains attached to the tube in both the partial-open and fully closed positions, eliminating the need to remove, set down, or search for a loose stopper when switching between incubation and storage modes.
Will these caps fit polystyrene (PS) test tubes?
No — these caps are specifically dimensioned for 12 mm polypropylene (PP) test tubes. For 12 mm PS tubes, Caplugs® Evergreen offers a separate variant with a different part number. Confirm your tube material and outer diameter before ordering.
Are these snap caps sterile?
No — they are supplied non-sterile in 1000/Bag bulk packaging. For applications requiring sterile closures, consult LabSupplies.com for available sterile alternatives or suitable gamma-irradiation protocols compatible with LDPE.