Single vs dual swivel head for boom arm?

I'm looking to add a basic boom arm to my lighting setup so that I can:
- Mount a speedlite overhead
- Better hold a reflector at different angles

The basics seem to come down to the actual swivel that allows the boom arm to be mounted to. It seems there are single and dual, but I'm not really sure why there even is a dual? What's the difference? All the shots just have the "2nd swivel gear" sitting on the light stand anyway?

http://www.ebay.com …3956c1:g:hWwAAO​SwpDdVH59r
http://www.ebay.com …0df851:g:XrkAAO​Sw6aVUq7lH

kaitlyn2004 wrote in post #17783623
I'm looking to add a basic boom arm to my lighting setup so that I can:
- Mount a speedlite overhead
- Better hold a reflector at different angles

The basics seem to come down to the actual swivel that allows the boom arm to be mounted to. It seems there are single and dual, but I'm not really sure why there even is a dual? What's the difference? All the shots just have the "2nd swivel gear" sitting on the light stand anyway?

http://www.ebay.com …3956c1:g:hWwAAO​SwpDdVH59r
http://www.ebay.com …0df851:g:XrkAAO​Sw6aVUq7lH

Iwould stay away from both of those. They are plastic and will wear out or break. Trust me, I speak from experience.

Scatterbrained wrote in post #17783625
Iwould stay away from both of those. They are plastic and will wear out or break. Trust me, I speak from experience.

What would you recommend?

a proper grip head and either a grip arm or a proper boom arm (depending on how much reach you need). Here's a kit with a grip head, 40" grip arm, and a c stand.

http://www.bhphotovide​o.com …ster_Century_C_​Stand.html

I have a few metal versions of those...they've held up well over 20+ years of use. It's not a bad solution to mounting an arm on a stand though it can be slightly awkward as the one clamp controls both the up and down movement as well as the in and out of the arm.

Here are some metal clamps;
http://www.bhphotovide​o.com …_bc_light_stand​_boom.html
http://www.bhphotovide​o.com …_D200_D200_Grip​_Head.html

I also can't imagine the advantage of the "dual"? But the impact I linked to is a metal version of it. The only thing I can see is that it may have more options for the diameter of the base rod vs. the standard style?