Arazas curtain
$35 free shipping conus

I used this with my duomid to give me air circulation in winter when buttoned down. works great.
I just unziped the door and the curtain kept out the snow but let plenty of air flow in.

also works with trailstar to block spray.
http://astucas.com/en/catalog?item-no=27-88

The Arazas curtain provides the additional protection you need when weather turns awry under a tarp or Trailstar. In addition, it provides some privacy on a camp site.

Details

Sized to fit the Trailstar and flat tarps of 2 - 2.5 m wide (130 cm wide x 85 cm high).
Cuber fiber laminate provides an exceptional strength to weight ratio.
3 attachment loops.
Apex loop can be secured with a mini carabiner (not included) or a knot.
LineLoc tensioners at the base for super easy setup and adjustment (guylines included).
Shock cords for an even easier setup.
Designed by Robin Evans.
25 g.
Made in Spain.