As a gift I received 25 of these things (the previous owner not knowing what they were). They're aprox 34cm in legnth. The orange bit is closed and doesn't detach, so I cant find any uses for it. The writing on it above the calibration reads... Regardless of their use I will most likely be selling them and I'd imagine they sell for more if I had a real description. If you want one or more I'll be sure to give you a discount. Thanks, Fezziwig.