Interesting mount for carry handles...what is it?

[Autopistola]

I was paging through Gun Digests book of the AR-15 (not sure which one).

I noticed a picture of a guy shooting an A2 style rifle which had a scope or light mounted to the right of the handle, right above the bolt assist.

Who makes this mount and has anybody tried it?

 

[macadore]

I got mine from Sportsmans' Guidehttp://www.sportsmansguide.com/net/cb/cb.aspx?a=691405 I am quite happy with it.