This kit is the rubbers only for the original Watts 007 double check assembly. It fits sizes 3/4" and 1". Originally the poppets were brass but they are now plastic and the rubbers are put into the poppets at the factory.
The original Watts 007 had a round thread on cover. The next version, the "M1" version has a square bolt on cover which uses four bolts to attach it to the body.