AliMed T-Gel Plus Cushion with a Solid Seat Insert incorporates a Solid Seat Insert base into the T-Gel Plus Cushion. The semirigid base fills in sling-seat sag to create a flatter, more stable sitting surface in sling-seat wheelchairs. 3-1/2" thick. 6 lbs., 7 oz. Choose black knit or ripstop nylon cover.