Keystone thumb. Top grain goatskin leather construction is the softest, most abrasion-resistant leather and is highly recommended for applications requiring tactile sensitivity. Top grain leather is smooth, provides durability and dexterity. Drivers gloves feature slip-on styling to provide good fit and comfort. Keystone thumb is ergonomic, reduces hand fatigue, offers superior dexterity and durability. Elastic closure sewn inside glove for safety and comfort. Cotton color binding denotes sizing.