They attach to your finger much like the ones they put on you in hospital to test your pulse. Looking at the information online it is done via infra red , if it works I have no idea. DH is a type 1 and has a Libra 2 type on script, but I know they are very expensive to buy and as a pre diabetic you would not be eligible. TBH I would try and just keep to a healthy diet , cutting down on processed food cutting down if you are a bit carbohydrate eater and to back to the nurse in 6 months for another test to see if it has worked before you go spending out on something that isn't that accurate. Take a look at " Diabetes UK website for some tips and more information.