Double Socket Swivel and Pivot Arm for 1" Ball, Plastic
This is the longest RAM B arm available. It is slightly longer, a bit lighter and much more adjustable than the RAM-B-201U-C arm.

The swivel and pivot action is very nice.  There are times when a standard RAM arm can't be positioned as desired because the "leg" attached to the ball can only go to one or the other side of the arm.  This swivel arm has a swivel/pivot joint in the center that allows the 2 ends to be set to multiple positions. 

The RAP-B-200-2U consists of double 1" diameter open ball sockets with a 360° rotation point at the center and a connecting swivel joint that rotates forward and back 180°. The rubber ball and socket at either end, and a central pivot point provides unsurpassed adjustability. The RAM ball sockets maximize ball coverage for optimal fit.

Don't think that it is not strong because it is made of plastic - it is very rugged. 

Length (center of socket to center of socket): 5.5 inches (140 mm)
Length with 2 x RAM-B-238U bases: 7.5 inch (191 mm)
Length with 2 x RAP-B-238U bases: 7.9 inches (201 mm)

Weight: 6.2 oz (176 g)