Each box of 25 comes with its own code chip which fits in the back of the meter. For accurate readings, this must be inserted (after removing the previous one) when you start a new box of strips.
1 box @ £41.46
2 boxes @ £39.54 each
3 boxes @ £37.80 each
4 or more boxes @ £36.18 each
The maximum shelf life is 12 months and the strips will only be effective for 2 months after first opening the tube (see box).