bannergrips
is a nice solution but, incurs HIGH MAINTENANCE. the systems has its flaws. trying to install this twenty feet up in windy conditions sucks. the "grip" parts slide in a rail system, which, can fall out while trying to install. the engineering part is not good in real world conditions. it took me an hour and a half with two people to install a 3'x12' there is another company that makes the same thing but their bracket system is better.