This is the Bypass Kit Used in the Hayward H Series, Ed1, Ed2 Heaters Made After 10-28-2000 Includes: Black Plastic Baffle, Round Plastic Bypass End, Stainless Bypass Shaft And Plug, Bypass Spring, And The Haxhor1930 Header O-Ring Length: 10" Width: 2-7/8 Total Height: 3-3/8 Markings: "0101421101" Is Molded Into The Bottom Special Note - The Bypass Kit For Earlier Heaters Uses Brass Fittings and The Baffle Is Shorter And Has Only 2 Holes Total