These new twist tubes are made of transparent polypropylene and feature a telescopic length extension, a twist-lock mechanism to retain extended position and a hexagon end to prevent rolling. The reusable tubes are rigid, durable, humidity- and oil-resistant. Available in three sizes. These adjustable tubes are ideal for safely transporting syringes and knives. Simply place the item inside, then screw it down until it fits snugly so it won't rattle around.