I bought a Vital Bow Gear 3 Ring Trappers sight which has a bubble level on the first pin ring. First thing I did after installing the sight was remover the first sight ring with the bubble. I shoot my bow an aweful lot to not know when it's level. IMO the bubble level is one more thing that can break your concentration while you're waiting at full draw for your shot to materialize. I'm not knocking those of you who use one but to me it's overkill. I draw my bow, I anchor, I settle the pin and then launch the arrow. I can honestly say I don't worry or think about canting my bow. (this coming from a guy who shoots a 30" ATA bow go figure)