High quality aluminum stirrups with rubber grip tread and spring loaded outside release for safety. When pressure is applied to outside of stirrup like in a fall the side of the stirrup will open all the way up allowing the foot to be released. No way to get hung up in these stirrups. (5 x 5 inside measurement, 7 outside height, 3 1/2 x 1 1/4 tread, .9 lbs.)