Some people have a hard time finding a mouth call that fits their mouth. Some people have the high pallet in the top of their mouth. You just have to try different sizes and find the one that is right for you. You may have to trim them up a bit along the edges to fit your mouth. If you just can't get one to work, you may just have to go with another style of call: box, slate, push, etc. Some people even like the tube calls. Just try different ones. Keep in mind that at times you will want to be hands-free to call and aim/shoot at the same time. Good luck.