The Mortar BombBlack Onyx Series(BOS) is Wicked Weights standard97% tungsten, 3% nickel flippingweight, with a few new features. Utilizing a chemical process to create a black oxide finish.You will also notice the addition of thestamped weightvisible on all BOS weights. This will allow you to grab the right weight every time, with no guesswork.Available in various weights to match your preferred presentation.