I’m no doubt late to this and going to get a dozen “hell, we’ve been doing this for years” responses, but it is new to me so I’m going to post.
I have been looking at covers for my EOTECH, C-MORE and other red dot sights and a bit put off by the prices that they command for what they are. Well today my wife asked me to grab a pair of socks for her. There on the top of her drawer were a pair of black ultra low cut “Peds” type no show shoe liners. Eureka! Nice stretchy nylon polyester fabric and an elastic band to hold it in place. Fits very nicely and looks pretty good too. Here’s one on a C-MORE Railway.