This is a new (some scuffing from handling) Winderen Flexi Mullen Mouth Bit in a size 135 mm or 5 1/4". This is the slim model, 14 mm. Better sized for the comfort of the horse.
It is made of a durable gel material that is comfortable and well accepted by the horse.
Designed for horses who need stability with gentle and even contact and for horses that prefer non metal bits.