The 550-RC has an outside jaw spread of 5 1/2” and an inside jaw spread of 4 3/4”. The cast jaw face is 3/8” thick and the offset is 3/16”. We’ve installed a Paws-I-Trip pan system and stainless steel night latch dog. Pan tension out of the box on the two coiled version runs an average of 2.5 pounds which we have found to be a very good number for a multi species trap. Pan tension on the four coiled model runs an average of 4.1 pounds. Waxing will decrease pan tension by about .3 pounds. This trap is fast and excellent results are obtained using it two coiled. We do not recommend using the 4-coiled version if grey fox is your target animal. The 550 is an excellent live market trap, as well as the trap to use on a mixed specie line. Small enough for fox and tough enough for the nastiest coyote. If you are not planning on 4-coiling your MB-550’s we recommend cutting the excess spring pins off leaving 1/2” protruding from the frame.