This adapter will NOT fit 1 1/2" or 1 1/4" vacuum hose. The hose OD is 1 1/2" and the vacuum hose OD is 1 1/2". 1 1/2 inches. The inside diameter of the sleeve is 1 1/4 inches. If your vacuum hose size matches the ID, you're in luck. But I've never seen a hose that size. The turning movement on this adapter is not smooth.