Scientists have created a portable blood glucose measure for diabetics which uses microwaves instead of pricking the skin.
Currently, diabetics have to test their blood several times a day or use inserted devices known as continuous blood glucose monitors (CGMs).
But a new monitor created by Cardiff University's School of Engineering can be discreetly stuck on to the skin.
Prof Adrian Porch said: "It will help with the management of the condition."
He added: "Conventional methods of monitoring blood glucose require the extraction of blood.
"Our device is non-invasive - it does not require the extraction of blood apart from the initial calibration."
Prof Porch said the monitor, developed with Dr Jan Beutler and Dr Heungjae Choi, can be stuck on to the arm or side of the body using an adhesive.
It also has a longer shelf-life because it is not chemical in its action.
The data it collects can then be monitored continuously on a computer or mobile app.
And while the idea of sticking a microwave emitter to someone's body may sound disconcerting, Prof Porch said it s entirely safe.
"It uses microwaves, but the levels are very, very low. Nowhere near the levels used in domestic cooking.
"Think about a mobile phone, we're about a thousand times less than that level."
Prof Stephen Luzio, of Swansea University's College of Medicine, carries out clinical research into diabetes and has overseen trials on about 50 patients using the device - with more planned this summer.
He said: "Patients are very keen on this. One of the big problems with patients measuring their glucose is they don't like pricking their finger, so there's a lot of interest."
People with diabetes have higher than normal blood sugar levels.
There are 3.5 million people diagnosed with diabetes in the UK, with an estimated 549,000 more who have the condition, but do not know it.
The 10% who have Type 1 diabetes have to monitor their blood glucose level more regularly - up to six times a day, or 20,000 times over a decade.
Cardiff University's diabetes monitor project started in 2008 and has since received £1m in funding from health improvement charity Wellcome Trust.
The team said the product is potentially five years away from reaching the market, subject to further investment.