The seriesOne shaft seal was designed for smaller, single-engine vessels with stainless steel propeller shafts. This shaft seal fits shaft diameters from 7/8” through 1 1/4” in 1/8” increments. It can also be used on metric stainless shafting from 25mm through 30mm. The seriesOne™ shaft seal is covered by a one year warranty. Tides Marine suggests that all twin-engine applications use the Tides SureSeal™.