I got mine from Harbor Freight for 5 bucks. It reads ounces grains grams and a couple more that I don't really use. It weighs up to 15000 grains and will really show how much moisture is going in and out of a bow just by the weight differance. I see 300 grain differances in weight of the same bow in just a few hours. I don't know what that means as far as moisture percentage but each bow has a specific weight at which I try maintain, and you can sure feel the differance of how hard the bow shoots when it is 300 grains lighter. I am amazed that much moisture by weight can transfer in and out of a bow size piece of wood in such a short time.