Ed Brown is a good brand Wilson Combat is a good brand. John Mason is a good brand. Brownells, EGW, MGW, Hogue, all good. It is not a critical component, and failure rate for a metal housing has got to be very, very low (I have never seen a steel one break). Just get a mainspring housing and replace it, it's not difficult (he says right before people start launching mainsprings all over the house). Also get the mainspring cap pin, some makers' guns don't have them. It holds the mainspring in the housing.