This D21258 Radial Ring Assembly is a complete redesign of the original equipment D21258 / D20604 that was a cast aluminum assembly.
The newly designed D21258 has a much better weight to heat ratio allowing the new radial ring assembly to run much cooler and longer than the original part.
The new D21258 Radial Ring Assembly is a high quality machined aluminum part and is a direct replacement for the original D21258 / D20604 that came on all of the oil free radial pumps produced for DeWalt, Ex-Cell, Porter Cable, Sears, Midwest Air, Coleman and other privately labeled pressure washers..
The redesigned D21258 Radial Ring Assembly comes with a 1 year replacement part warranty and will provide a much longer life than the original D21258 Radial Ring assembly.
The D20604 is the casting number for just the old style aluminum housing without the bearing.
The replacement for the D20604 is the D21258 Radial Rings Assembly with the bearing already installed.