1 Piece square key wrench spanner tool includes sizes 8 mm, 10 mm, 12 mm, 14 mm and 17 mm for general use on lathe chucks and other engineering tools, offering versatility across CNC routers, engraving, milling machines and metalworking applications Material and finish: carbon steel with black oxide treatment and heat tempering for lasting performance under heavy duty conditions, resisting wear, damage and erosion during prolonged operation Grip design: embossed T handle to forestall slippage, delivering a firm stable hold even when applying torque to tighten or loosen the chuck safely and efficiently Use scenario 1: ideal for changing or tightening lathe chucks and related fixtures on milling machines Use scenario 2: suitable for CNC router setup, engraving and metalworking tasks that require secure torque and reliable grip Use scenario 3: practical for routine chuck maintenance and tool adjustments during long machining sessions