Blue Steel Taping Knife for applying second coat of compound to drywall joints and covering drywall screw holes. Aluminum backing plates provide blade rigidity while making these knives up to 40%. Blue Steel blade doesn't show rust. Hollow poly handle is molded to the extruded aluminum backing plate so it can't come loose. Blade flares out at edges to reach into corners. Professional grade tool. Safe to use with chemical solvents.