This is an insert for Dewalt Toughcases to hold standard sized utility blades. It should work in all ToughCase and ToughCase+ storage boxes. Each holder holds 15 blades give or take, depending on the thickness of the spring.
To insert blades, push them into the blade slot and push the blade against the springs when it is at the bottom. Just repeat until you get about 15 blades.
To remove the blade pinch the blades and lift up with your finger or thumb (whichever is touching the outside blade).