It's a free sample of Go Splash Strawberry Watermelon!
Go Splash (for those of you who don't know) is a highly concentrated flavouring for water with sweeteners and vitamins.
I've seen a few people with the portable packs, but I've never tried it myself. Please excuse me while I go grab a glass of water to try it out...
...good news - it's absolutely delicious and seriously fun to do. PLUS it's turned the water a pretty shade of pinky-orange.
You can choose as little or as much as you want - "personalise your drink your way" as the folks at Go Splash say.
If you choose to buy a full-size product (which I plan to do this lunch because this flavour is super-yummy), here is some information you might want to know about:
It comes in a handy 48ml pocket-size bottle
Makes 6 litres of flavoured water
No added sugar, low calorie (less than 2 kcal a glass)
Does not need refridgeration