The Semco model 850 gun is a hand-operated, high quality dispensing gun designed to accept Semco disposable cartridges or Semkit packages. It is suitable for the “in-field” application of sealants, adhesives, and other materials. The ratchet handle is made of metal for tough, durable, long-term use. A threaded retainer provides a tight fit into the ratchet handle, permitting uninterrupted operation. It also allows for the quick and easy replacement of cartridges. Custom size retainers accommodate Semco 1, 2.5, 6, 8, 12, 20, 32 oz., and 1/10 gallon disposable cartridges. The retainers are available in metal or plastic.