Abbey Hard Rubber Mullen Gag A non flexible rubber mullen gag stronger than the bendy style. Also available in Vulcanite. £86.95 imperial size: [Choose]5.1/2"6" Quantity: at £86.95 each Add To Basket A nice kind comfortable gag for horses that dislike a jointed bit. Available in a soft bendy rubber mouthpiece. 53/4"and 6" bits are more expensive.