Nalgene Quick Connect Articulated Bite Valve Conversion Kit

This is a good product but seems to be getting hard to find. It is relatively inexpensive so I ordered 3 from an online retailer just to have a few spares for the next several years.

It is great when using a Katadyn Hiker filter, since the filter comes equipped with compatible discharge hose fittings. Great for filling a reservoir without removing it from the pack. The swivel shutoff valve is great, even though I haven't had an issue with it leaking through the bite valve while the valve is open. 

The magnetic clip is also a nice feature, allowing the bite valve to be attached to the sternum strap to keep it from swinging around. Overall a good product.

My only issue is that it does not come with a male hose fitting for your filter. (As I mentioned, the Katadyn comes equiped with the male fitting, so I was not too dissapointed. In addition, the quick connect fitting kit is available from Katadyn pretty cheap, so it could be adapted to Katadyn or other filters pretty easily.)