The MB43LP Myler Low Ported Barrel Narrow Pelham is a solid curved mouthpiece with a 1 inch port to allow tongue room using a centre barrel that acts as a swivel joint on each end of it to provide for independent side movement that assist with lift through the acting shoulder. It gives lots of tongue room, does not collapse but it will roll down onto the tongue when the horses head is too far forward. Can be good for strong and keen horse who has a tendency to lean on the bit.