This Diamond R 6 in. Argentine Low Port Bit with Copper Inlay Roller provides plenty of room for the horse's tongue to pass underneath, and when engaged does not rotate onto the tongue. The center barrel has limited movement to prevent the bit from scissoring down into the tongue or up into the palate. The copper roller provides some movement helping to pacify the nervous horse. The bit's Argentine cheeks offer versatility, hooking reins to the middle rings offers direct rein pressure or moving reins down to the teardrop rings and adding a curb chain provides leverage.