Leather Inserts For Greenguard Grazing Muzzles - HORSE SIZE (5)
 
These help protect the horses teeth and the muzzle from wear. I found the muzzles can get dirt or sand ingrained in them that wear on the horses teeth, this helps prevent that. 
 
This is vegetable tanned leather 4-5 mm thick. You can use medium and/or small size zip ties to attach the tabs on the leather to the basket. You do not have to drill any holes in the muzzle to attach these. 
Sorry I do not own a Pony (4) or Mini (3) size of those muzzles, I can only make horse size (5) ones.