We like chains. Which is why our own observatory’s roof is moved by chain. This drive system is mounted between the 16″ on center studs in your wall and will reliably open and close your roof year after year. Using standard 40 pitch chain in either nickel plate or stainless steel, its very quiet and smooth when installed with spring tensioners on the chain bolts. Contact us today to discuss this option for you larger roofs and to obtain a quote.