Eliminate the pain associated with fighting the fenders.
Made of top-quality 1/8" hand-polished, no-rust aluminum molded under 7000 lb of pressure. Placed between your existing Western stirrup and fender keeps the stirrup set at a right angle to the horse. This allows the stirrup to correctly align your foot with knees and hips, eliminating "fender torque" and related knee pain.
Size choices: 2½" or 3".
(Note: Size choice is a measurement of the bottom width of the stirrup fender.)
I like the Cashel EZ Knees, have had mine 5 years, they really relief torque on knees. I wouldn't ride without them. Regarding the metal hitting your shins, I have no problem with it...I wear roper style thick leather boots that protect my shins.
Like the other reviews say, these are very uncomfortable. The metal part hits you sharply right in the shin, and there is no way to correct it. Also, it appears that you need the fender to keep your leg in the right position, and this makes the position of your leg on the curve of the fender wrong making riding with these even more uncomfortable. Total waste of money.