I have struts which are almost new. When I bought my Avionic AVG-15 4 years ago the original struts (1100 N) turned out to be a little too light, because my outer wings are attached to the clamshell. So after a few weeks I changed them for 1200 N variants. My original ones are for sale, but I live in Europe........
The brand name of the struts is AL-KO. I bought them at a local trailer shop. I do not know if this brand is available in the US.