The tapered edges are to keep them from squeeling or chattering. I believe the slit is for dust and gasses and water... Brad B. Phx AZ '96 200sx SE-R(w/ this 'n' that) '01 Altima GXE LE > All the OEM pads I've seen have the cut through them like that, and the > leading and trailing edges tapered down as well. Dunno why. I guess the > slit is to help expell dust or water?