Bivi bag. MkII by pushbikemike, on Flickr

Silnylon base layer with bathtub construction. Pertex top. Mesh netting. Two way double zip runs across mesh and 2 feet down side. Room inside for mat and down bag. Actually my winter bag fits in no bother.

Weight is 350g with mesh stuff sack.

Lessons learned:
1. sizing is generous. Could trim weight by making smaller.

2. Could use lighter top material.

3. Zip was from an old tent. Could use smaller and lighter zip

Looks ace Mike, the sizing was generous on mine too but better too big than too small I think. Where did you source your pertex?

Cheers ray.
Point north fabrics for the pertex.
Although I now think this was Skylon material which is like pertex.

That looks cracking Mike ... top job.

Cheers. I'm well pleased with it.