more teeth can be provided and it is also possible to provide teeth on the rear side of the blade the precise shape and size of the teeth can also be altered it is presently preferred that the teeth 46 not extend beyond the adjacent side edge 50 of the blade 16 the teeth 46 also are preferably not offset from the plane of the blade in this manner the blade 16 will avoid snags and binding yet will pulverize the brittle glass and break the tough flexible plastic lamination both during the upstroke and the downstroke a presently preferred blade is approximately 3 4 inches in length the shank 44 is preferably about 0 5 1 inch in length preferably about 0 8 inches the section of the blade with teeth 46 is preferably about one half inch in length the relief of the teeth is preferably about 0 05 0 15 inch most preferably about 0 12 inch while the radius of the cutting face of the teeth is preferably about 0 5 1 0 inch most preferably about 0 7 inches the distance between the leading edge of the teeth and the end of the blade is preferably about 0 25 0 5 inch most preferably about 0 4 inches the tip 54 of the blade preferably is pointed to facilitate the piercing of the glass and plastic lamination by the blade particularly during the initial penetration of the windshield this pointed tip can also be used as.