Reinsman Western D-ring snaffle. 3" rings, 5" mouth with 1/4" square slow twist.
 
"The Dee ring applies pressure to the horse's cheek on the opposite side of the face from the rein you pull to allow better flexion. This mouthpiece with tender up the lips and bars to add control. Excellent for a horse lugging on the bit. Sweet iron promotes salivation for a supple feeling mouth."