This product is installed between your fender and your stirrup on your western saddle and turns your stirrups out 90° for you. Since your feet don't have to hold the stirrup turned out while you ride, this product greatly reduces the fatigue on your ankles and knees. My husband has bad knees and this product really helps reduce the amount of knee pain he experiences when he rides-and he rides in a 25 year old, well-broken in saddle. The only problem I've found is that they don't seem to work well with the endurance type metal stirrups. I tried using them on my saddle with this type of stirrup, and it caused the tops of the metal stirrup to poke me in the leg just above my ankle. That did not happen when I had traditional leather covered stirrups. Cost for this product ranges between $18 and $30, depending on which of the two brands you purchase and where. The Stirrup Straights are made from powder-coated steel, and the Cashel E-Z Knees are made from aluminum. Both come with the screws, sleeves to protect the screw threads and your fenders, and the nuts to secure them. You will need a standard (flat) screwdriver and a wrench to install these on your saddle.