Caplugs® Evergreen
Test Tubes, LDPE, Natural — 300-3812-02P | 1000/Bag | Caplugs® Evergreen
Test Tubes, LDPE, Natural — 300-3812-02P | 1000/Bag | Caplugs® Evergreen
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Two-Position Snap Caps, For 12 mm PP Test Tubes, LDPE, Natural — 300-3812-02P | 1000/Bag
| Quick Reference — 300-3812-02P | |
|---|---|
| Tube Format | 12 mm PP test tubes |
| Cap Type | Two-position snap cap (partial-open + fully closed) |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Natural |
| Position 1 | Partial-open — allows gas exchange during incubation |
| Position 2 | Fully closed — sealed for storage and transport |
| vs Stoppers | Snap cap stays attached between positions; stopper must be removed |
| Sterility | Non-Sterile |
| Pack Size | 1000 / Bag |
| Price | $56.57 / Bag ($0.0566 / cap) |
Technical Narrative
The Caplugs® Evergreen is an LDPE two-position snap cap for 12 mm PP test tubes — a cap that provides two distinct functional positions without being removed from the tube. The partial-open (first snap) position holds the cap ajar, allowing CO₂ and O₂ gas exchange during microbiology culture tube incubation — maintaining the aerobic or microaerophilic atmosphere required by the growing culture without contamination risk from an uncapped tube. The fully-closed (second snap) position seals the tube completely for refrigerated storage, frozen archiving, and transport without contamination risk.
The two-position snap cap's key workflow advantage over a simple stopper cap is that it remains attached to the tube throughout both positions — eliminating the need to set down, find, or replace a loose cap when switching between incubation (partial-open) and storage (closed) modes. LDPE construction provides the flex required for the snap-position engagement mechanism across the repeated open/close cycling of a microbiology culture workflow. The PP tube variant is specifically dimensioned for 12 mm PP test tubes — the PS variant (300-3812-02S) fits 12 mm PS tubes.
At $56.57 per 1000/Bag — $0.0566 per cap. For 12 mm PS tubes, see 300-3812-02S ($56.57/1000).
Technical Specifications — Caplugs® Evergreen
| Specification | Value |
|---|---|
| Part Number | |
| Caplugs Item # | 300381202PE1 |
| 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 |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Natural |
| vs PS variant | Same cap; 300-3812-02S fits 12 mm PS tubes |
| Sterility | Non-Sterile |
| Pack Size | 1000 / Bag |
| BPA/Phthalate | BPA-free; no phthalate plasticizers |
| Country of Origin | Made in U.S.A. (California) |
Two-Position Snap Cap Application Compatibility — 12 mm PP
The LDPE snap cap fits 12 mm PP test tubes for workflows requiring both gas exchange and sealed closure:
| Application | Tube / Specimen | Notes |
|---|---|---|
| 12 mm test tube closure | 12 mm OD culture and test tubes | Two-position snap: partial open (gas exchange) or fully closed |
| Microbiology culture tube capping | Broth culture tubes (TSB, BHI, LB) | Partial-open position allows CO2/O2 exchange during incubation |
| Sealed storage position | Refrigerated or frozen tube storage | Closed position provides sealed contamination-free storage |
| Clinical chemistry tube closure | Sample tubes staged before analysis | Closed position prevents evaporation during pre-analytical hold |
| Cell culture tube capping | Suspension culture, virus propagation tubes | Partial-open for gas exchange; closed for transport |
| Sequential open/close cycling | Tubes accessed multiple times per workflow | Two-position snap allows repeated open/close without degradation |
| Environmental sampling | Field collection tube closure | Closed snap position for transport; open for field sampling |
| Color routing (natural cap) | Universal tube cap for any labeling system | Natural LDPE cap for secondary label identification |
Validate snap-cap fit with your specific tube brand. For PS tubes, use 300-3812-02S.
Chemical Resistance — Low-Density Polyethylene (LDPE)
LDPE provides flexibility for snap-cap position engagement and inertness to culture media and specimen matrices.
| Reagent / Condition | Compatibility |
|---|---|
| Aqueous buffers / water | ✓ Excellent |
| Urine / serum / plasma | ✓ Excellent |
| Dilute acids (<10%) | ✓ Good |
| Short-chain alcohols (brief) | ✓ Good |
| DMSO (≤10%) | ✓ Good |
| Autoclave (121°C) | ✗ Not compatible — LDPE softens |
| Storage at -20°C | ✓ Suitable — LDPE retains flexibility |
300-3812 Two-Position Snap Cap Tube Variants
| Part Number | Tube Material | Price/1000 |
|---|---|---|
| 12 mm PP | $56.57 | |
| 300-3812-02S | 12 mm PS | $56.57 |
Laboratory Applications
The serves microbiology labs running broth culture in 12 mm PP tubes where gas exchange during incubation and sealed storage between runs are sequential requirements; clinical microbiology programs using 12 mm culture tubes; cell culture programs using 12 mm tubes requiring vented incubation; and any 12 mm PP tube workflow requiring the two-position partial-open / fully-closed cap functionality.
U.S. Manufacturing, Quality & Institutional Procurement
Every Caplugs® Evergreen lot is precision-molded at our California manufacturing facility. We supply reference laboratories, hospital systems, and federal procurement offices under institutional pricing programs with blanket-order support and same-day shipping. Request a free sample below to validate fit before committing to volume.
Frequently Asked Questions — Caplugs® Evergreen
What are the two positions on the two-position snap cap?
Position 1 (partial-open / first snap): the cap is held ajar by the first snap engagement — a small gap allows gas exchange for culture tube incubation while preventing uncontrolled contamination from open tubes. Position 2 (fully closed / second snap): the cap is fully seated for sealed tube storage and transport. The cap remains attached to the tube in both positions — no loose cap to set down or misplace between incubation and storage cycles.
What is the difference between the PP variant and the PS variant (300-3812-02S)?
Both are LDPE two-position snap caps for 12 mm test tubes — the only difference is the tube material they are dimensioned for. fits 12 mm PP (PP) test tubes. 300-3812-02S fits 12 mm PS (PS) test tubes. PP and PS test tubes can have slightly different wall thicknesses for the same OD, requiring different snap cap dimensions for positive retention. Always validate with a sample before bulk purchase.
Can the two-position snap cap be used as a full stopper replacement?
The two-position snap cap functions as a tube closure in both positions, but the partial-open position is specifically designed for gas exchange — it is not a fully sealed closure. For applications requiring a complete hermetic seal in all conditions, use LDPE stopper caps (300-2912 series for 12 mm tubes) which provide full friction-fit closure when inserted. The two-position snap cap is the correct choice when alternating between vented incubation and sealed storage without cap removal is the workflow requirement.
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