Threshold is a lightweight yet portable wheelchair ramp designed for doorways, sliding glass doors, and raised landings. Threshold ramps may be used either one by itself or two combined to make entry and/or exit convenient and safe. Simply measure the height of the door entry and choose the correct size. Manufactured using high-strength aluminum (will not rust or corrode) and features an extruded non-skid driving surface. Easy installation. Supports up to 600 pounds and features a 3-year limited warranty.