Globe Scientific's plastic microhematocrit capillary tubes are completely unbreakable. They eliminate the risk of injury and contamination associated with glass tubes due to breakage. Plastic microhematocrit capillary tubes comply with FDA, NIOSH, CDC, and OSHA safety recommendations. The tubes are available plain or with an anticoagulant (sodium or ammonium heparin) that keeps the blood from clotting. All of the tubes have color-coded ends to easily identify the plain and heparin-treated tubes. Types of TubesUntreated: Blue TipAmmonium Heparinized: Green TipSodium Heparinized: Red Tip Packaging: 100 tubes per vial, 10 vials per box (1000 tubes per box) Material: PETGID: 0.90mm ± 0.05mmOD: 1.60mm ± 0.05mmLength: 75mm ± 0.05mmVolume: 45uLSpin rate: 12,000 RPM for 4 minutesLatex Free NOTE: Only use plastic capillary tubes on micro-hematocrit centrifuge rotors that support the entire length of the tube. If the rotor only supports the tubes at two points, the tubes will bend and the sample will be lost. For rotors that support two points, use our glass capillary tubes. If collecting anti-coagulated blood from a blood collection tube, use a plain capillary tube. If collecting by finger stick from a patient or when using untreated blood, use capillary tubes that are treated with an anticoagulant (heparin).