The ProSite Professional Level Series box-beam levels are designed and manufactured with ribs to maximize strength and stability and allow for easy add-on accessories. The magnified horizontal vial with large bubble makes it easier to read accurately. Levels feature a glare-resistant setting with luminous base for easy reading in dimly lit areas. The solid block acrylic barrel-shaped vials are readable upside down with the same accuracy as right-side up and are shock-proof, leak-proof, fog-proof and virutally unbreakable under normal working conditions. Adjustable vials make it easy to set grades accurately and re-calibrate to level or plumb.