Saddle pad from Mattes.

Classic all-purpose saddle pad with quilted top and hook-and-loop fastener that makes it easy to attach to the saddle to prevent it from shifting under the saddle.

Use a measuring tape to measure the length of the contact area on the underside of your saddle. Then add 6 cm to know the minimum length your saddle pad should be. The measurements may vary by +/- 2 cm. The saddle pad may shrink by about 5% during washing in some cases.