TFL Thru Hull : Single water pickup. Available in black or silver.To install these, drill a hole to match the inner circle's diameter to recess the fitting flush with the hull bottom, then use epoxy to glue it into the hull. Available in two sizes:- M4 Size: Width 16mmDepth 2.5mm Height 18mm- M6 Size: Width 22mmDepth 2.8mm Height 22mmWorks with 1/4", 9/32", 6mm or 8mm water tubing.