I don't want this to sound like advertorial 'cause it's not, but we just received a Geigerrig 500 hydration pack in the post and this thing is a game changer. Let's ignore the fact that our test model is fluoroescent green (or Citrus as they like to call it), this pack is so different to your standard hydration pack it's not funny. There really only is one difference, but it's a biggie: the Geigerrig sprays. You don't have to suck at all, just bite down and the water comes flying into your mouth. Kind of like Reebok Pumps of old, the pack has a pump on your left shoulder strap which you... um... pump; the bladder is divided in two and the air filled side pushes against the water filled side and sprays it out. Pretty damn simple. One of the best bits is that the people behind this pack, instead of trying to develop their own bladder from scratch (which no doubt would have had teething problems) approached industry bladder leader Hydrapak to develop the unique pressurised system. It's definitely more reassuring than if it had been its own inhouse bladder. It should be added that one of the main reasons for the development of the Geigerrig system was that the guy behind it was a marine and with water sploshing round in his army issue hydration pack he couldn't be that covert; an added bonus of the pressurised bladder is the water never makes a sound!
The pack itself is reasonably standard but features all you need in a simple hydration pack: a waterproof iPod pocket, a large main compartment and two smaller outer pockets for cellphones and tools, two compression straps as well as gear loops. It even features a pretty swanky aerated harness. There are also three larger models to choose from if you want to carry more gear.
And seriously for me, one of the best bits about the whole Giegerrig system is the inline water filtration system. Now this isn't a purifier, this is a proper filter that removes 99% of Giardia and cryptosporidium so if you are rocking the inline filter you will be able to fill up your bladder from any stream, river or creek in New Zealand.