Springfield Economy Jon Boat Seat Clamp - 8" to 19" [1100012]Economy Jon Boat Seat Clamp 8" to 19" Jon Boat Seat Clamp Adjusts From 8 To 19 To Fit Most Bench Seats. E Coated Steel To Resist Corrosion. WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings. ca. gov.