This kit fits older 1990-95 Chevrolet Suburban & Tahoe (NEW BODY STYLE) that have the DUAL MALE threaded style fittings with O-rings. Thread sizes for this kit are: 5/8" - 18 tpi Male Insert O-ring and 1 1/16" - 14 tpi Male Insert O-ring. NOTE PLEASE: Some 1990's used the old style connections (one being male and the larger being female), this kit does NOT fit such applications. Easy to install by any proficient technician by simply disconnecting the rear lines in the engine compartment and install the kit. The kit allows for front A/C to remain fully functional while eliminating the rear system without the loss of refrigerant from the rear lines or evaporator. No need to replace expensively the rear A/C lines or evaporator. Lead to a quality cold air. The fittings are at the connection location of the rear lines.