The name is the promise of accuracy. This beautifully machined 5 X 45 degree square is guaranteed accurate to .001 from heel to toe. Made with a hefty 1/4 thick solid aluminum alloy body each square is machined from a single piece eliminating the potential alignment errors that can occur when a separate blade is manually assembled to a separate handle.The one piece body won t get bent out of shape if accidentally dropped and the anodized blade and body won t tarnish like brass. Pretty to look at but so accurate it will be a constant work companion. USA