Microcentrifuge Tubes Precision molded microcentrifuge tubes are available in an assortment of sizes and colors to meet your needs. Low friction siliconized tubes are also available. 15ml Centrifuge Tube and Plug Cap These 15ml conical centrifuge tubes, made from premium polystyrene or polypropylene, offer results of precision and accuracy. Screw Cap Centrifuge Tubes Premium quality general purpose centrifuge tubes with optional printed graduations. These tubes are easy to read, provide superior clarity and durability, are available with various packaging options, and provide a leakproof seal.