The Zeus 990 is the toughest level on earth. With all of the features that professional contractors actually need to get the job done right. Added value features include: the Plumb Site Dual-View vial (on both ends of the level), a magnified horizontal vial, air-cushioned shockproof end caps, air-cushioned wall-grip handles, 2 milled surfaces, and non-stick wipe-clean Keflon coating. Levels fall. All the time. They get knocked about and dirtied up a fair bit, too. That's why professional contractors need a level that can take it. When it falls, they want to be able to pick it up, wipe it off, and get straight back to work. They need to know that its frame is straight, its vials remain perfectly accurate, and all that's needed is a cloth to wipe it clean.