I have sold a ton of these and wanted to post up here as well. These are made from 550 paracord and connect to the D-Rings of your tac vest/chest rig and the lower arm attaches to the sling mount on your buttstock. I have three available at the moment:
1) Groundwar Camo
2) Coyote Tan
3) O.D. Green
They are $35 (which includes shipping in the CONUS). I would be willing to ship to Canada, but shipping would be more. PayPal only
Here is a pic with on eon my Chest Rig: