HIGH QUALITY STEEL MATERIAL, ZINC PLATED FINISH SIZE IS CLEARLY MARKED ON EACH PIECE. KEYSTOCK IS USED TO PROVIDE DRIVING TORQUE BETWEEN SHAFTS AND PULLEYS, GEARS, SPROCKETS, ETC. USED FOR NEW MACHINERY, GENERAL MAINTENANCE AND SHOP REPAIRS. IT IS A NECESSITY IN ALL APPLICATIONS WHERE ROTATING POWER DEVICES ARE USED. MOST TOLERANCES ON DIMENSIONS ARE OVERSIZED TO ASSURE TIGHT FITS IN KEYWAYS FOR POSITIVE, ZERO BACKLASH POWER TRANSMISSION.