The 300mm and 11-3/4" Combination Set with Square features a reversible lock bolt, scriber, spirit level in both square head and protractor head, direct reading double 180° protractor scale, and hardened steel, and photo-engraved blade. FEATURES: Reversible lock bolts, scriber, spirit level in both square head and protractor head. Direct reading double 180 Deg protractor scale. Direct reading double 180 Deg protractor scale. Non-reversable protractor head. Hardened steel, machine divided blade. Regular Finish Blade. Cast Iron Heads with Black Wrinkle Finish.