Bike bottle cages are one of those essential items for every cyclist. If you're cycling for more than an hour, it's vital that you re-hydrate your body with water and hydration tablets. Many cyclists have two bottle cages on longer cycles to achieve this, ensuring that you get the right hydration from water as well as required electrolytes back in your system, allowing you to safely continue enjoying your cycle and push your performance to the limits.
There's a wide range of bottle cages available, from old school, no nonsense steel cages to the latest carbon fibre models for the weight-conscious cyclist. Most cages will fit standard sports bottles, with a slight flexibility in the design to fit those bigger bottles in, so sizing is never really an issue.