I had old original Irwin Heavy Duty clamps - they fit but needed sanding/forming - original pads apparently not available (looked heavy) - so didn't like them , had to reshape the shoe support on the longer part of the shoe to fit the clamp but after I shaped them they worked just as well/or better than new ones - my clamps lasted about 10 years and I use them almost daily - the original pads started to work just about to fail now - so glad i found these replacement parts - but if the original pads were available this would be a 5 star rating