This is a new 7/8" straight thread x 1/2" compression check valve for older Campbell Hausfeld, Speedaire or Sears air compressor. This is a special check valve made for these compressors it has a 7/8" male straight thread that screws into the tank with a high temperature gasket seal. Some of the original valves that this is designed to replace were made of aluminum and some were brass; this will replace either one.

*Note this will not work on all Speedaire, Campbell, and Sears compressors most of them have regular pipe thread check valves.*

How to tell if this is the right one for yours: if it is the same, yours will have an aluminum or brass ring that seals it between the check valve and the tank. If your compressor has that ring this will work for you. This valve also has a 1/8" female NPT port in the side for an unloader, some didn't have that port, if yours doesn't you can easily plug it with a 1/8" NPT brass plug (available at your local hardware store). The tank thread size of this valve is called a 7/8" x 14 straight thread. 

Here are some of the models this will fit Speedaire: 3z323B,3z395B,3z355B, Campbell Hausfeld VT558701,VT558701AJ VS4001,VS400100AJ and Sears 106.153681, 106.153781, 106.152581, 106.170641,106.154580,106.17554. 

Please double check sizes to make sure it will work even if yours is one of these models.

Specifications:

Valve Inlet Threads: 1/2" Compression (measure about 5/8" outside diameter)

Outlet / Tank Threads: 7/8" Male Straight Threads

Side Port: 1/8" Female NPT (measures about 10/32 inside diameter)

Total Length: 2-5/8"