Body-Solid GAB350 Semi-Recumbent Synchronized Ab Bench Clamshell design ensures proper form and total ab workout Incredibly effective in isolating the entire abdominal region Adjustable seat pad, roller bar (4 range of motion adjustments) an foothold to fit all users Provides maximum user comfort by positioning and stabilizing the lower back To increase resistance - add weights to the plate holder near feet. Used with Olympic Weight Plates Only.