Seat clamp clamp seatm with swivel clamp on boat seat swivel adjusts from 7 1/2" 18" black powder coated swivel fits most seat hold patterns.. Features Seat mount clamp-on with swivel; Specifications Color: Black; Finish: Black powder coated; Dimension: 8.5 x 14.38 x 6.38 in.; Weight: 8.53 lbs; .