It makes filling your Osprey reservoir easier which is always welcome.
I have a Platypus Gravity Works Filter System. Will this connector allow me to filter and back flush into my Osprey reservoir?
Yes, the Quick Connect Hydration Hose Kit is compatible with your Platypus Gravity Works Filter System.
I hike with an MSR mini-works EX. My Camelbak plugs right into the output of the filter, so I can fill it without even taking it out of the pack. Does some part of this kit allow me to do the same for the Osprey Bladder?
Yes, the Osprey Quick Connect Hydration Hose Kit will allow you to pump water directly from your MSR MiniWorks EX Water Filter to you Osprey reservoir.
can this be used with a camelback? I'd like to swap out the tubing for my camelbak 50oz
This kit will work with a Camelbak. You could use the CamelBak Quick Link Conversion Kit for the same purpose:
How long is the hose that comes with the kit?
The length of the included hose is 8 inches.