From Marcrist
The Marcrist Extension rod is for use with the dust extraction unit. It attaches to the core drill bit and the dust extraction unit to give an extra 150mm (6in) or 300mm (12in) length depending on your requirement and choice.Features & Benefits High quality Long lasting Type: Extension rod Thread: 1/2" BSP Female to Male Proven reliable Marcrist technology High performace for the home or tradesman Warranty: 1 year