Katadyn Mini Filter
I bought this new and used it a couple of times...it just wasn't what I was looking for. The output hose has a Platypus attachment. I maintained the filter after use and it's in near-new condition.
Price new $65, asking $20 including shipping via Priority Mail.
Here's a link to see specs on this item:
Payment by PalPal please - will ship immediately. I'm listing several items, if you want to order more than one I can combine some of the shipping costs.