Every now and then a new invention hits the shelves that's at once so simple and so useful, it leaves you wondering why nobody thought of this before, the Source Convertube is one such item.  This clever adaptor tube will convert your water bottle into a hydration system.  It works with Sigg, Nalgene or mineral water bottles, fits through the ports of any hydration compatible back pack, and uses antibacterial technology to keep your water tasting fresh.

We're big fans of the full Source hydration systems, but the company also has an option for those who don't want to invest in a full reservoir but still want the benefits of hands-free drinking in the form of the Source ConverTube, which converts a standard mineral water, Sigg or Nalgene bottle into a hydration system.

The ConverTube comes with a Source Z valve complete with anti-bacterial layer in the tube, grunge guard system and dirt shield to reduce the chances of bacteria and mould growth.

Three adaptors mean you can use either a standard-issue mineral water bottle, a Nalgene bottle or a Sigg one. To use it, you simply adjust the retractable tube to the height of your chosen bottle, fill with water and screw the ConverTube universal cap onto the bottle.

At a suggested retail of £15.99, the ConverTube isn't that much cheaper than a full Source reservoir, but then arguably, in some situations, it's more versatile and gives you the choice between using a normal bottle, a disposable one or going hands-free.