Stainless Steel with loose rings. The wings not only prevent the bit from being pulled through the horse's mouth, but exert lip pressure when the reins are used.
This is a very popular all-round bit. It should not be confused with the USA version of the Tom Thumb, which is a completely different model bit.
Shetland/Small Pony Size (4"/10cm)
Mouth Thickness 13mm
Ring Size 50mm