Mossy Oak Biologic Bio Rock is 100% natural solid mineral rock salt, not a compressed mineral lick. It is used to attract deer, keep them coming back, and help them reach their full potential. Lasts much longer than a typical salt lick. Contains over 84 trace minerals including ones believed to promote deer health and antler growth. Key minerals include calcium, potassium, and sulfur. Slowly dissolves into the soil to create long-lasting, frequently visited site. Use this deer mineral rock salt according to your local laws and regulations.