Concord Blades CONV-WDS Core Bit Adapter 1-1/4"-7 M to 5/8"-11 F for 3 to 6" Core Bits Male Thread Size 1-1/4"-7mm (M) Female Thread Size 5/8"-11mm For use with 6" to 14" wet core bits that have the 1-1/4"-7 female threaded