This model fits 0.25" (1/4") tubing.

Fill your hydration pack without removing it from your back pack!
Hydration pack not pictured and not included.

The blue screw on adapter will be connected to the 'filler tube' when you receive it.

1. Cut the tube going to your 'bite valve' off about an inch and a half from the 'bite valve'.

2. On the 'bite valve' portion push the male 'quick disconnect' connector completely on the tubing.

3. On the hydration bladder side push the female 'quick disconnect' connector completely on the tubing.

4. Take the filler tube with the second male 'quick release' connector and screw it on to your Sawyer SP131 or Sawyer SP181.

Now you can remove your bite valve and connect your filter to push clean water into your hydration pack.

This item will also work with the Sawyer Mini SP128 but it does not fit directly out of the box, you will have to remove the blue screw on adapter and push it onto the filter semi-permanently. It fits pretty tight to the filter so removal is not the easiest.

If you check out my Accessory category in my eBay store http://stores.ebay.com/ecoverve/Accessories-/_i.html?_fsub=846522019 you will find several items that may help you create your ideal setup, let me know if you want to mix and match any of the “compatible” adapters. I can make a custom setup with a mix and match of "compatible" parts.