The men's Altamont Reynolds Sweater in a Medium size is 28" long, has a 21" pit to pit width, and a 20" inner sleeve length. The men's Altamont Reynolds Sweater in a Small size is 27" long, has a 19" pit to pit width, and a 19" inner sleeve length. I measured the inner sleeve because there really is no outer shoulder hem to reference.
The men's Altamont Reynolds Sweater is still on backorder and not physically at the warehouse yet. Please resubmit your question when stock shows available and then I can certainly get out to the warehouse to get the dimensions you are asking of.