This D&D PowerDrive V-belt is designed to deliver maximum performance and durability for your mechanical power transmission needs. With a special outer covering designed for smooth clutching and backside, this belt can resist extreme temperatures, high humidity, oil, and cracking. It is a perfect fit for your DURA-ULTIMATE 4LK370 or A35K Aramid V-belt needs. The belt is 4LK 1/2 x 37in OC (AK35) and is suitable for use in various industrial automation and motion control applications.