I have never used that particular strop before, but it should work very well. Generally speaking most of the best leather strops are made from horsehide rather than cowhide. Horsehide is very dense and non-porous making it much more durable than cowhide. The top of the line horsehide strops are made from what is called "shell" horsehide. The shell of the horse is the subcutaneous layer of tissue and muscle below the hide.

The strops you purchased were made from the "butt" and will be from the toughest part of the horsehide and of excellent quality leather. they should work well and last a lifetime if taken care of.