Have a look at this article on increased productivity when using a dual monitor.

Increase Productivity by 10% with DUAL MONITOR WORKING

Immediate improvement in comfort for the multiple computer screen user.

No need to twist and turn, all your information is in front of you.

Productivity increases when all  information you need is easily visible from the one position.

This KPA-series is an elegant rail system with un-matched flexibility for table mounting.

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Specification:

Pole height: 850 mm

2 x Bar Length: 1600mm

Maximum Table Top: 85mm

6 Monitor Arms

K81A Monitor Arms, 3 pivot axis length 240 mm.

or

K71A Monitor Arms: 2 pivot axis length 125 mm.