Checkpoint 300 Ultra-mag G3 8-1/2-inch 4-vial Platinum Magnetic Torpedo Level Plus Bonus Level Keychain! Non-laser ultra magnetic torpedo level; water and shockproof 4 precision-aligned vials, extra-large V-groove system parallels up to 10-foot diameter Neodymium magnet system and aluminum alloy construction Available in multiple colors; 8-1/2-inches long Lifetime guarantee