For outboard engines, a rugged see-thru bowl lets you visually monitor filter effectiveness. Inboard engine applications require a metal bowl. Accumulated water is easily drained from the collection bowl. When the filter element is replaced, the bowl is reused. The kit includes a new bowl which spins right onto the filter element. All MFG. numbers with "B" as the fourth letter are complete assemblies consisting of spin-on filter element and see-thru or metal bowl. 10 Micron - Replaces OMC 174144 See thru bowl (Outboard only) 1"