Strong Aluminum profile with reinforcing ribs - for stability and secure hold. End Cap with an anti-slip feature for a firm grip when marking walls. Shock absorbing endcaps protect frame when dropped. Removable end caps allow exact positioning and marking right up into corners. Easy to clean. Spirit level with two precision-milled measuring surfaces. (up to 48", coated from 72"). STABILA vial installation technology ensures long-term accuracy - suitable for measuring in normal and upside down positions.