yeah I had a 1.5 adapter, but I bought the one with the silicone hose adapters and set screws!! i wasn't paying attention. oh well at least I know now. if I don't like it I know someone who would. I prefer the t grip like the overused B&M t grip shifter knob that weight a gazillion pounds I have now. I can get an adapter at a local hardware store for like .25 cents