I have 2 of these tools that are possibly to seat bushings or bearings. Threaded end is M12x1.5 go to a smooth 20mm diameter sleeve to a 28mm sleeve. Hex is 24mm. Possibly from Assenmacher Specialty Tools. Overall length is 6" and weight is 0.95 lbs.
Tell what it is and I'll cover the shipping cost. 1 per customer.