*15 Key Rings: Smaller for pocket or purse.Usually high pitched. *30Survival: Placed on suede leather of various colors. Selected to always have a loud clear tone. A true quality signal whistle. The survival whistles usually sell the best. *25Burl, Double, Unusual: Because of the nature of antler, double, burl and unusual whistles can only be made in limited quantities. There will be 25 total from these three types in each standard assortment. Burl- that unique portion from the base of the antler. Double- made from the fork of the antler; Two distinct whistles. Unusual- antlers usually grow symmetrically but aberrations do occur; Extra points and unusual gnarls make distinctive whistles.