For those who lost their flip sight covers (I did, several times) during skirmishes, you can find replacements at Airsoft Supplier UK.... "This is a set for the front and rear of a 30mm sight. They are an essential upgrade for any sight that does not have them as the lens covers act as protective barriers to bodies which may scratch the sight lens when or when not in use. They can also stop light reflecting off the front lens when not in use, potentially giving away your position on a sunny day!"