The Chinese knockoff sights are pretty bad. The covers on the other hand work perfect. My cousin bought a couple of the knockoff sights. Put them on AR style air rifles. They work, but obvious that they suck. Now their finish on the other hand actually looks better than actual C-mores. The dot is probably 2-3MOA on them. One, the battery cover screw stripped out immediately.
Some say you can put a C-more dot module in them and they work great. Do that crap at your own risk. We tried just for the heck of it, and you would have to sand down the C-more module for it to fit. Nope. I'm not modifying a $50 module to fit inside a $30 knockoff sight.
Lastly, as far as those covers go, they are more for looks to me (albeit I have 2 of them). I've never had a C-more Railway wash out in the sun in the middle of the summer.