Nuun Electrolyte Water Additive, 

1 Tablet in your water provides all the essential electrolyte requirements for any form of exercise without the sugar. Nuun is an excellent high quality product backed by serious scientific research, Water is good Nuun +water is better still.  Drop 1 tab in your water bottle and by the time you’ve tied your laces or put on your pack, you’ve got a complex electrolyte drink that recharges your salts, its refreshing and more efficiently absorbed than water alone or most sports drinks on the market.

What is NUUN ? nuun turns every water fountain into a source of optimal, balanced  hydration

OK how does it work? nuun hydrates you more quickly.  here's why

Faq? Are there any calories in nuun? find out here