Created exclusively for Ordnance Survey by Water To Go, this 75cl water bottle includes a built-in filter to eliminate over 99.9% of all bacteria, viruses, chlorine, fluoride, and heavy metals such as lead - leaving you with safe and healthy water. You can use it to improve your everyday drinking water in the office or at the gym, or take it out and about to reduce the amount of water you have to carry while walking or camping. This bottle can filter water from almost any source, aside from salt-water. It is BPA free, ensuring no nasty chemicals can leach into your water even if left unopened for a while. Each bottle comes with a filter that lasts approximately 2 months (around 130 litres) and includes a unique timer to track the filter life. You can get replacement filters from Water To Go.