The I/O Port Racing Supplies Seat Bracket is designed to fit most aluminum racing seats. Mounting holes are 9.5" on center. The aluminum brackets bolt to the side of the seat and are adjustable for height and tilt. The base of this bracket is not drilled. These brackets are furnished with hardware to mount the brackets to the seat. Order one SB02 to mount one seat. The brackets must be used with a seat back brace.