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Caplugs® Evergreen

Test Tube Stoppers, LDPE, Blue — 300-2917-B2N | 1000/Bag | Caplugs® Evergreen

Test Tube Stoppers, LDPE, Blue — 300-2917-B2N | 1000/Bag | Caplugs® Evergreen

Regular price $53.19
Regular price Sale price $53.19
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Test Tube Stopper Caps for 17 mm Test Tubes, LDPE, Blue — 300-2917-B2N | 1000/Bag

Quick Reference — 300-2917-B2N
Tube OD 17 mm
Cap Type Stopper (plug-in friction fit)
Material Low-Density Polyethylene (LDPE)
Color Blue
Tube Types 17 × 100 mm and 17 × 120 mm glass and PS culture tubes
Temp Range -20°C to +60°C (LDPE flex range)
Sterility Non-Sterile
Pack Size 1000 / Bag
Price $53.19 / Bag ($0.0532 / stopper)

Technical Narrative

The Caplugs® Evergreen is a blue LDPE stopper cap for 17 mm OD test tubes — designed for 17 mm OD test tubes used in larger culture, clinical chemistry, and specialty tube formats. The 17 mm stopper serves large-format culture tube and specialty clinical tube workflows. Blue stoppers mirror the CLSI H3 blue-top citrate anticoagulant convention for 17 mm tubes — used to designate citrate specimen batches and for post-collection closure of coagulation and citrate tube formats.

LDPE's low-density flex modulus provides the compression and spring-back required for friction-fit stopper retention across repeated insertion/removal cycles — the property that makes LDPE the only appropriate material for stopper-style tube caps. LDPE retains flexibility from -20°C through 60°C, preventing brittle failure during frozen archive stopper removal and maintaining seal engagement during incubation. Chemical inertness to serum, plasma, broth media, and aqueous buffers ensures no leaching into tube contents.

At $53.19 per 1000/Bag — $0.0532 per stopper. Also available: 300-2916-020 (Natural 16 mm, $66.96); 300-2912-B20 (Blue 12 mm, $44.13).

Technical Specifications — Caplugs® Evergreen

Specification Value
Part Number
Caplugs Item # 3002917B2NE1
Tube OD 17 mm
Cap Style Stopper — plug-in friction fit
Material Low-Density Polyethylene (LDPE)
Color Blue
Tube Compat. 17 × 100 mm and 17 × 120 mm glass and PS culture tubes
Temp Range -20°C to +60°C
Sterility Non-Sterile
Pack Size 1000 / Bag
BPA/Phthalate BPA-free; no phthalate plasticizers
Country of Origin Made in U.S.A. (California)

Test Tube Stopper Application Compatibility — 17 mm

The 17 mm blue stopper fits standard 17 mm OD tubes for these workflows:

Application Specimen / Use Notes
Culture tube capping Microbiology culture tubes, TSB, BHI, LB broth LDPE stopper seals tube during incubation; flex retained at 37°C
Specimen tube archiving Serum, plasma, blood in refrigerated/frozen storage Prevents evaporation during extended cold storage
Clinical tube color routing CLSI-convention color stoppers for specimen-type ID Color stop mirrors vacuum tube top-color conventions
Cell culture tube capping Suspension culture, virus propagation Stopper allows gas exchange while preventing contamination
Pneumatic tube transport Sample tube transport in clinical systems LDPE flex retention survives transport acceleration forces
Chemistry tube sealing Pre-analysis sample tube closure LDPE inert to serum/plasma; no leaching into specimen
Research reagent tubes Buffer, reagent, stock solution tube archiving Stopper seals reusable glass and PS tubes between uses
Hematology / coagulation EDTA, citrate anticoagulant tube formats Color-coded stoppers for anticoagulant tube designation

Always validate stopper fit with your specific tube brand — 17 mm OD tubes vary in opening diameter by wall thickness. Request a free sample before bulk purchase.

Chemical Resistance — Low-Density Polyethylene (LDPE)

LDPE provides flexibility for friction-fit stopper retention and inertness to clinical specimen matrices.

Reagent / Condition Compatibility
Aqueous buffers / water ✓ Excellent
Urine / serum / plasma ✓ Excellent
Cell culture media ✓ Excellent
Dilute acids (<10%) ✓ Good
Dilute alkalies (pH <12) ✓ Good
Short-chain alcohols (brief) ✓ Good
DMSO (≤10%) ✓ Good — brief contact
Autoclave (121°C) ✗ Not compatible
Storage at -20°C ✓ Suitable — LDPE retains flexibility

Laboratory Applications

The serves microbiology culture tube programs, clinical chemistry and hematology tube archiving, and any laboratory requiring friction-fit sealed closure on 17 mm OD test tubes.

U.S. Manufacturing, Quality & Institutional Procurement

Every Caplugs® Evergreen lot is precision-molded at our California manufacturing facility and subject to rigorous dimensional inspection and material purity verification. 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 tube formats use 17 mm OD and fit the stopper?

The fits 17 mm outer diameter test tubes, including: 17 × 100 mm and 17 × 120 mm glass and PS culture tubes, specialty clinical chemistry and serology tubes. Always validate fit with a sample before bulk purchase — opening diameter varies within the 17 mm OD range by wall thickness.

What is the clinical convention for blue 17 mm tube stoppers?

Blue stoppers mirror the CLSI H3 blue-top sodium citrate anticoagulant convention for 17 mm tube formats — used for post-collection closure of citrate coagulation tubes (PT, aPTT, fibrinogen) and for designating citrate specimen batches in 17 mm tube color-coded routing systems. All 17 mm stoppers are identical in LDPE material and performance.

Why is LDPE used for stopper caps rather than PP or PS?

Stopper-style caps work by friction fit — the plug must compress under insertion and spring back against the tube inner wall. PP and PS are too rigid for this and crack under repeated insertion/removal cycles. LDPE's low-density flex allows thousands of insertion cycles without fracture, retains flexibility at -20°C to prevent brittle failure, and provides chemical inertness to clinical specimen matrices.

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