Reversible lock bolt allows blade to be turned over or end-for-end, without removing the lock bolt or nut. Multi-purpose uses include. 45° miter, depth gage, height gage, marking or scribing gage, a level, a plumb, and a precision rule. Spirit level in square and protractor heads. Forged and hardened steel square heads and center heads, cast iron protractor head with smooth black finish. Center head accurately finds center of round work. Steel scriber. Protractor head has direct reading, double 180° scale. Hardened, machine divided graduations, blade.