High-quality, autoclavable polypropylene “reaction” tubes. The snug-fitting shield-shape hinged caps are readily manipulated with one hand, yet will stay closed during use. Added thickness at tubes’ conical bottoms prevents failure and leakage. The standard 1.5-mL (10.6 × 39.5 mm) tubes have frosted writing areas. Available in three colors in dispenser boxes of 500.