Screw/seal assemblies are used to attach the fuel transmitter to the aircraft's fuel tanks.  

The screws used in Cessna aircraft are made of stainless steel and feature hex wrenching on the head. The hex head does not require severe or extreme down pressure to tighten or loosen the screws as do the Phillips head screws used by Cessna. This down pressure can bend or distort the soft aluminum fuel tank.

The seals are a special Viton rubber Stat-O Seal that do not degrade or swell with avgas and are built into a special stainless steel washer. The seals replace Cessna P/N S350 cork seals that degrade with time and cause leakage.