Woodson: I always carry a Buck Model 317.
This knife is a folding model and has two blades that are right at 4" long.
This models thicker blade can easily "saw" through the sternum (rib cage) of a Deer for ease of cleaning - with a two hand hold on the handle.
Then the more slender 4" blade is PERFECT for reaming and removing the digestive tract outlet of Deer (and Elk!).
Several other knife makers have EXACT "copies" of this versatile knife including Puma, Case, Schrade and Sears as well as a couple other lesser known makers.
With the two blades of this model I always have a razor sharp blade in case I wish to do some caping or another animal.
This nifty knife will fit in a pocket but anymore I carry it on my belt in a custom sheath as they do not come with a sheath from Buck.
Hold into the wind
VarmintGuy