I acquired my Krok Drop from PetrenkoWorld in 2007.
The Drop consists of a pivoting lever and a fixed anvil mounted between two side plates. One side plate is stationary, while the other pivots on the lever axle so that it may be opened to admit the rope. The anvil is attached to the rear face plate with two rivets, one of which is extended to engage a notch in the front face plate.
The Drop is painted with the same mottled paint used on the Krok Bug, Half Crab, and Fish. There are no markings on the Drop.
The Drop is a small reliable, but inefficient ascender. It operates on the same principles as the Camp Lift, Russian Versions A and B, and various Ural Alp ascenders. To rig the Drop, follow the instructions given for the Camp Lift. As with all ascenders of this type, there is a significant lost motion with each step. I wouldn't choose the Drop for a long climb, but it's small size makes it attractive for short, remote drops.