The drip free self aligning Tides Marine SureSeal FSKM-50M-80M-1 inboard propeller shaft seal is made from fiber-reinforced composite material, and is unaffected by temperature and will not absorb water. Order your Tides Marine SureSeal FSKM-50M-80M-1 prop shaft seals today from Deep Blue Yacht Supply and save. The Tides Marine SureSeal FSKM-50M-80M-1 measures Shaft Size: 50 mm, Stern Tube O.D.: 80 mm, Compressed Length: 184 mm