The PocketEar. Not to be activated at Metallica concerts I suspect! �65.80.

‘With PocketEar it is possible to measure sound in your environment – this is for your protection in case a certain limit is crossed…Any time you want to know how loud it is at the moment you can activate PocketEar with one key press…When the volume you set before is crossed, PocketEar will flash yellow and if it stays like this for a longer time it will flash in alarming red.’