
These Reducing Sleeves, or inserts as many people call them, are to reduce the internal sizes of a particular pipe to enable a slightly smaller pipe to fit the connection, whether that connection is to a socket, bend or some other fitting - they should, of course, be solvent welded into place prior to the actual pipe connection being made.
Reducing sleeves enable the use of ball valves, slide valves and other fittings with solvent weld waste piping as well as PVC pressure pipe. Simply glue over the end of the solvent weld pipe before fitting to the appropriate valve or fitting. One required for each side of the valve.