Shims for the Ultra ThinLine Felt Liner Western Pad are available for the front, rear, or bridge section of the pad. These are one size shims to fit the western pad. Sold in pairs. Choose front, rear, or bridge - each shim set is sold separately. The Ultra ThinLine Shims are 3/16" closed cell foam, the thinnest ThinLine material. The shims help fill in saddle gaps to create a better fit, all the while adding even more cushioning and shock absorption. The western pad has a pocket on each side to slip in the shims. Once inserted, the shims do not move. Shims make the Felt Liner Pad more versatile so it can be used on a variety of horses and with different saddles. Inserts are sold by the pair, separately. The Front set has 2 front shims, the Rear set has 2 rear riser shims, and the Bridge set has 2 shims for the center of the pad. These Ultra ThinLine Shims are designed specifically to fit the Ultra ThinLine Felt Liner Western Half Pad available at Mary's.