dexcom transmitter

Hello, I bought a transmitter with already changed batteries. Please tell me in what ways it will be better to change the batteries and than will need it later to close? I buy Maxell SR1120W

Just taken the plunge and purchased a Dexcom G4 transmitter with sensors and was wondering if the transmitter can be insured - Tried with my bank who have stated they can not insure the transmitter as it holds no storage therefore not classed as a 'Gadget' but a medical device. Has anyone...