Comparison : Item # SDSM-500-1300-2C, 1/2" x 13" SDS Max Shank 2 Cutter Carbide Drill Bit 7-1/2" Usable Length
Item # SDSM-500-1700-2C, 1/2" x 17" SDS Max Shank 2 Cutter Carbide Drill Bit 12" Usable Length
Item # SDSM-500-2100-2C, 1/2" x 21" SDS Max Shank 2 Cutter Carbide Drill Bit 15-1/2" Usable Length
Item # SDSM-563-1300-2C, 9/16" x 13" SDS Max Shank 2 Cutter Carbide Drill Bit 8" Usable Length
Item # SDSM-563-2100-2C, 9/16" x 21" SDS Max Shank 2 Cutter Carbide Drill Bit 17" Usable Length