Some men claim to be endowed with a highly accurate "internal thermostat" and some women will tell you that they definitely didn't turn the central-heating up. Here to settle these churlish debates once and for all is Thermodo.
This exceptionally precise piece of equipment plugs discreetly into the audio port of your smartphone and allows you to measure the temperature in any given environment. Just pair it up with the free app and watch the instantaneous live readings rise and fall, there's even a very clever function that compensates for the heat your device and body give off.
Constructed from a scratch-proof aluminium and attached to a handy keychain, you can now experience accurate temperature readings from the palm of your hand, wherever you are.