Heller allmat sds plus universal drill bits heller 21680 7 this allmat universal drill bit from heller is suitable for use with a wide range of materials including masonry tile glass marble plastics metals laminated chipboard and breeze block this 8 x 100 x 160mm bit has a diamond ground carbide cutting edge and sds plus shank heller 21680 7 3718 allmat sds plus universal drill bit 8 x 100 x 160mm