The Ultra ThinLine Trifecta Full Sheepskin Half Pad . Ultra ThinLine over a high-quality quilted cotton half pad with luxurious merino wool sheepskin underneath. It has a lovely contoured profile with plently of wither clearance. The shock absorbing Ultra ThinLine create a spine free channel give your horse extra comfort. This design allows the Ultra ThinLine to lay on either side of the spine so that it provides a spine clearance channel while keeping all the sheepskin against your horse for comfort and protection.