Therafin-31695-Drop Seat Insert for 19" ChairStandard Solid Drop Seats that come with pre drilled holes and 16 T Nuts that you can insert where needed. Pre drilled holes include the abductor and hinge holes. They are made from 1 2" thick 9 ply birch wood and are painted black. No hardware is included. Additional items that may be needed are the Swingtabs and Rail Locks (50474) and a Drop Hook Kit.