Reinsman Performance Wonder Gag Bit. Very popular gag shank with cheeks that allows the mouthpiece to move forward when reins are pulled to give the horse time to think before the curb chain and mouthpiece tighten. Excellent mouthpiece for horses who need a little more control. Sweet iron is intended to rust and promotes salivation which makes a more supple feeling mouth. 7” Cheeks • 5” Mouth • 7/16”.