The WTF Grunt'R uses Inflection Chamber Technology to mimic the natural inflection in sounds made my rutting deer. Compress, expand or bend the chamber to instantly change the sound of your call. The chamber can even cut off airflow, creating the sound of an out-of-breath buck. Tru-Touch buttons for failure-proof doe and fawn sounds plus a durable snort wheeze chamber will enhance your call library even more.