@Casper60
On youtube is a posting all about using a cardboard template about 10cm x 8cm with a rectangular shape cut out of it so that the template can be put over the sensor and adhesive and keep secured a lot longer than 14 days. The tape Opsite is called Flexifix and its what is being used to demonstrate how it goes on the skin with the sensor. Opsite flexlifix is available in 10cm x 1 metre rolls but it is expensive. An alternative is Tegaderm but an even cheaper option is ClearFilm which comes in 10cm x 12cm patches of 10 in a pack. A patch cut in half would be ok being 10cm x 6cm and then the shape cut out of it to go over the sensor. Ive found something at home that can be used for the shape and that is from the oval cap on a small bottle of shower creme (S'Burys own brand). The oval shape goes over the G4 nicely

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This is what I do with good success..........wipe the skin first really well with alcohol swab first to remove any shower soap residue and debris. Go about 10cmx6cm. Using the cardboard template, mark the skin with the point of Biro pen in the 4 corners. Then wipe the skin with the swab, let the area dry and then insert the sensor. Let the sensor adhesive dry out on the skin for about 10-15mins and then get a SkinTac swab (MG, UK) and carefully wearing a pair of disposable gloves, hold the wipe by its edges and wipe over the sensor adhesive and within the 4 Biro marks on the skin. Let the tac go sticky and then peel off the backing paper to the Opsite, Tegaderm, etc and place over the sensor and the skin. Its best to take off the disposable glove before handling the tape and keep a small bowl of water to dip your fingers in so that no tac is on the fingers. After using the SkinTac fold it over and add a drop of surgical spirit to it and place back in the sachet and seal it up with some sellotape and store in the fridge to prevent it drying out.
Ive found that I dont have to apply more Opsite unless its edges start to peel away as most of the time, the SkinTac keeps it held in place but if it does, then its easy to cut off a bit more Opsite and lay on top. The tapes can be bought on eBay or Amazon but there are loads more that can probably be used but Opsite, Tegaderm or ClearFilm is going to be the right size.
I havent long been using the G4 sensor but the past 2 have worked all ok for about 3 weeks and even when the symbols ??? or ANT show, it doesnt necessarily mean that the sensor has finished. Often the sensor will start to transmit again within about 30min but might not be as accurate but most of the time the G4 is fairly good (Look at all the msgs left by
@Spiker) Be resourceful, try not to get the sensor wet too often (tape a piece of plastic sandwich bag over the 10x6cm area and use something like Transpore waterproof tape to keep the bag in place when having a shower (I think I saw waterproof medical tape sold in one of the £ shops)
To remove the transmitter from the sensor, a 5p coin if used carefully can enable the 2 transmitter grips to pull away so that it can be lifted off with the sensor still on the skin. The elephant shape can also be used but the 5p coin is good as are the thumb nails.
Hope this helps you a bit.......