We are offering pipet pipette filler bulb silicone, black these pipet fillers are made of 100 percent silicone rubber. Chemically resistant with a greater chemical resilience than natural rubber fillers. Designed to accommodate pipets up to 25ml with a quarter inch diameter opening. Designed with standard three valve system. Also available in red. Total length: 5.91 inch (150mm) bottom stem length: 2.64 inch (67mm)