This water bottle has a two-part design that allows it to compact to half its size

Platypus has announced that in spring 2016 it will release a new bottle that combines a hard upper half with a collapsible lower half. The intention, according to the brand, is to offer the ease of drinking of a hard bottle and the packability of a soft one.
The Meta Bottle will be available in 750ml (£16) and 1-litre (£18) versions, both will be compatible with Platypus’s Microfilter system. This is an accessory that turns the bottle into a personal water filter able to remove bacteria and protozoa from up to 1,000 litres of water.
A 1-litre Meta Bottle with a Microfilter will retail at £40.