Description_x000D_ General description_x000D_ The O-ring secured in the top of the cap ensures a positive leakproof seal, time after time, keeping the integrity of small samples under even the most adverse conditions._x000D_ Caps are supplied with attachment loops, and allow them to remain attached to the tube in order to prevent mix-up and contamination._x000D_ • Perfect for cryogenic work_x000D_ • Non skirted tubes can be centrifuged up to 20,000g. (skirted 17,000g.)_x000D_ • Will withstand temperatures from -196°C to +121°C_x000D_ Please note: Do not immerse during liquid phase of liquid nitrogen.