Dave Bishop gave me this accessory
http://www.bhphotovideo.com/c/product/656152-REG/Impact_9101880_Umbrella_Bracket_with_Adjustable.html
Looks like it accomplishes the same thing as my Posi-Lok clutch, but in a slick little package. Might be worth replacing my Posi-Lok to save a bit of space in the gear bag.
Does the variable angle elbow joint lock down tight enough to hold extension + mics at a substantially horizontal angle, e.g. 0º, 15º, 30º, 45º, 60º from horizontal? Reason I ask is I sometimes clamp off balcony rails and need something that can hold my extension / mics not just down (or up), but also quite a ways out / horizontally. The Posi-Lok clutch is
very secure in this regard. (And, of course, I use safety cables / safety rope.) But that thing is damn cool and looks mighty small.