Inlet size = Adapter size?

In the first place the inlet size (diameter) of your air tool may measure 1/2in from side to side but pipe thread size is not measured that way.

What you need is 1/4in NTP (national pipe thread) Female quick - connect coupler and I/4in male thread stud that fits the coupler and your impact tool.

Go to Sears.com and click on tools and then in the search box type in "air compressor accessory kits".

You didn't tell me what size your hose is or if it has a connector on it.

My guess is that it is also 1/4in. hose and if it doesn't already have a connector on the end of the hose for the quick connector you will probably also have to buy a new hose.

A fool proof method is to disconnect your existing hose from the compressor and take it and your tool with you to sears and tell the sales rep. you need to attach one to the other but it's important to purchase the quick-connect coupler because in the future you are probably going to have other tools you can attach to that hose like an air ratchet, blow gun, tire inflater, etc. This way you can change from one tool to another without having to unscrew anything.

The air hose fittings you should be using is 1/4" NPT "National Taper Pipe Thread" brass air tool fittings normally found at any Home Depot, Lowes or hardware store. The also have to types of fittings, one where the locking mechanism is locked in a small round channel on the fitting and the other has a raised collar around the fitting for the tool to fit on to