I bought this item and later realised that there was a more expensive item in the range and was slightly concerned that it might not be up to the job. In the event, I found that there was nothing to worry about and, for the home workshop, this is more than adequate. You will need a female coupling to screw onto the screw-thread that comes with the tyre inflator and, I found that you may need some ptfe tape to make it air-tight. The thread is compatible with 1/4 inch fittings and XF fittings, depending on the compresor you have. On use, there is a clip that attaches securely to the filler valve on tyres and the dial will spin round to about 4 bar until you release the trigger, at which point it will fall back give you a reading in psi and bar. Obviously, it would be better if the dial was progressive and gave a true reading as you fill - I was disconcerted at first - but it does not matter that much and the cost saving against a professional product makes it good value for money, but not perfect. If this is crucial, go for something better, but for the home workshop, this is adequate and for the price works very well.