29 Long Can Be Used With Either Standard Arm Or Desk Arm Wheelchairs Double Notches Allow The Board To Be Used On Either The Right Side Or Left Side Of The Wheelchair Constructed Of Plywood And Finished With A Smooth Lacquered Finish The 24 Board Has One Built-in Handle While The 29 Board Has Two Built In Handles Notch Designed To Fit Into Up-right Of Wheelchair Arm For Added Security During Transfer Supports Up To 300 Lbs