These Apollo™ series levels have a heavy-duty aluminum box frame with a red powder coat finish, shock absorbing end caps and are calibrated to an accuracy of .0005" per lineal inch. They also have two plumb vials, including one Plumb Site™ solid acrylic vial that allows the plumb vial to be easily read from the front through the use of a mirror mounted within the level. All levels have a single, large level vial with two milled reading surfaces and two (one for No. 985-41X-24) hand holes featuring the nonslip rubber Ergo Grip™ on one side that prevents sliding when used on walls. The solid acrylic vials of all levels are unconditionally guaranteed for life against losing accuracy, leaking or breaking. Levels are 1" wide x 2-3/8" high.