Rhythm beads are pretty and practical. They often soothe a tense or distracted horse. The rider can "hear" the rhythm = a teaching aid in learning to post the trot; and also allows you to hear when your horse is "off." Trail riders benefit, as deer, hunters, and other riders can hear you coming around bends in the trail. Gaited riders love how these enhance their horse's rhythmic gaits.
To use, simply slip the "horse necklace" over your horse's head and attach the clip to the mane hair at the withers to secure in place.