Grant Top Line HD Series Box Track, 8 Foot, Anodized Finish, Hardware Kit, 325 Lbs. The Top Line Grant HD Series is a heavy duty commercial and residential grade sliding door hardware series ideal for single and bi-parting installations. It has a weight capacity of 325 lbs. per door. Applications include the movement of heavy panels, space dividers or large doors. This kit is designed for one 4 foot door with 4 feet of travel.