VEVOR Demolition Jack Hammer, 3500W Jack Hammer Concrete Breaker, 1900 BPM Heavy Duty Electric Jack Hammer, 2pcs Chisel with Gloves & 360° Swiveling Front Handle for Trenching and Breaking Holes

Thank you very much for your answer. Yes, the VEVOR 3500W Demolition Jack Hammer (Model JH-65) uses a standard 65A chuck system, which accepts 1-1/8 inch (30 mm) hex shank bits with a retaining notch/collar.

Yes, it can accept a 1 & 1/8 bit. The official size from Vevor is 30MM. 30MM is between 1 & 1/8 and 1 & 3/16 so either bit works. When shopping for bits, if you search on 30MM, you don't get many hits. Search using either US fraction. I have purchased many bits where the packaging says 1 & 1/8 hex, but they actually measure 1 & 3/16. Be sure they have a hex fitting with a slot. I have the 3500 model.