Round serrated face is 1-1/4" diameter. Square face is 1-1/8" x 1-1/8". Cross-grooved face for shrinking sheet metal . Plain square face for flattening. Made in the USA Martin auto body tools are the choice of professionals because of their superior quality. This Martin hammer features a precise-ground head with excellent balance, the proper weight, and a fiberglass handle. Fiberglass handles are becoming popular because of their comfortable grip and ability to absorb shock. All Martin Tools carry a limited lifetime warranty.