Teflon tape contributes to making a screw coupling airtight, which is required for connecting accessories to a water pump. Even the smallest amount of air may cause a water pump to malfunction, Teflon tape ensures that screw couplings remain tightly connected to each other. Simply apply Teflon tape to a screw coupling with a male (external) thread, then screw both parts onto each other. The tape is an indispensable aid to installing a water pump. Profec Sealing tape PTFE 12 mm white 10m 0070011 0070011