Works great on my 90hp Johnson 2 stroke. Great clamping force and all metal construction. Covers the water intake completely and tightly and the water stream from the "pee hole" is very strong. It does work on my 25hp Johnson, but not very well. The stream coming out of the "Pee Hole" is very weak unless I squeeze on the muffs with my hands. I plan on getting the correct "circular" style muffs for the 25hp.