This mount is very heavy duty but the 48\ TV I was mounting only weighed 17 lbs so cannot say about a heavy TV. I had no problem extending the arm and swinging the TV to one side so it was 90 degrees to the wall. This single arm with the off center attachment to the wall bracket comes in very handy for applications where you want to swing the TV to the side. You could swing the TV almost 180 degrees so it can be watched from either side of a room or anywhere in between. I plan to buy another for a customer that wants to put a TV in an older TV Cabinet that has an opening smaller than the TV. The TV will be outside the cabinet but will need to extend so you can get to the wires. The long arm and off center attachment will allow me to mount it to the side of the cabinet since it is too deep to put at the back.If I had a very heavy TV and it just needed to move in and out with smaller left and right swing I would use a twin arm for more strength."