We've had plenty of people get ahold of us to ask if we had replacement screws for their Holosuns and we finally do!  These screws are compatible with the following optics:
407/507k
407/507C
507Competition
508/509T
 
Our kit includes:
(2) replacement battery tray screws
(1) hex key
(1) blister pack of VC-3 thread locker