Glenn, that's why there has been such a run on Evernew water bags for the past year or so! (Of course Evernew production was severely disrupted by the Japanese tsunami, too.) At some point in the past few years, Platypus decided to go to non-standard threads. The older Platys with straight sides are fine; the newer ones with curved sides are not. I did see one recent report that Cascade Designs came to its senses and went back to the regular threads, but that's strictly one report.

The standard soda or drinking water bottle works fine with the Sawyer Squeeze, too (I've not only read this but tested it). So do the caps for these bottles. Smart Water bottles, for one, are flexible enough to take lots of squeezing.

I changed from Platypus to Evernew water bottles in 2010 because I got sick and tired of losing Platypus caps. Evernew caps are attached with a toggle, so no need to carry extra caps! Plus, soda/water bottle caps won't fit the newer Platys, which means purchasing Platypus caps.

There was a report on BPL that using a different size washer (a hose washer) made the newer Platys work with the Squeeze. I didn't note the details because I'd already switched to Evernew bottles.

Now that I've written this, I find that Evernew bottles are still "not currently available"! I know that a number of outfits (Gossamer Gear, Mountain Laurel Designs) received some a month or two ago. Evidently they are still selling as fast as they come in! Amazon.com carries them and they're out, too. Sorry to get everyone's hopes up!