Recently I bought a 20L Exped shrink bag and schnozzel. As they are unavailable in the UK, I had to order from Unterwegs in Germany. German prices are little different from UK prices for comparable products, but shipping was quite expensive at €13.80. The picture above shows the uncompressed size.The picture below shows the compressed size with an Alpkit Pipedream 600 sleeping bag. The “valve” is actually just a hole with a flap to seal, but it works fine. It is certainly effective in compressing a bulky sleeping bag, if you kneel on the shrink bag.
I’ve also bought a Synmat UL (which I’ll post on at a later date). I was intrigued by the schnozzel attachment to convert the shrink bag into a pump. The concept is similar to the pump bag Exped provided with their original down mats. Because the shrink bag is 20L, it is much more effective as a pump than the original smaller pump bags. It takes around five goes to fully inflate the Synmat. It’s a lot easier than blowing up by mouth. As with all Exped products, the quality is unimpeachable. Both products are well worth considering if you have an Exped mat. Weights are 182g for the shrink bag and 26g for the schnozzel.