The M21 feature the very popular "Carson Flipper" blade extension, which aids opening and acts as an additional blade guard.

Kit Carson's open build uses contoured handles of 6061 T6 aluminum, hard anodized charcoal gray. They are CNC machined with a perimeter radius for a comfortable grip with or without work gloves, skeletonized to reduce weight. There is a single stainless steel locking liner with friction grooves for positive locking.

Columbia River has also incorporated the patented Lake And Walker Knife Safety (LAWKS®) into the M21 models, which converts them into virtual fixed blades when engaged.

Every model features a removable Teflon plated stainless steel pocket clip.