While the PK01-VS
is the lowest factory red dot that I am aware of it is
unfortunately almost impossible to find at this time.
Fortunately two new red dots are on the market that
are almost as low as the VS and are much easier to
find, at least as of 2012...PK01-V and PK-A Venezuela.
PK01-V is almost exactly the same height as VS due to the interesting side rail mount, and fortunately is much more accessible here in the USA than the -VS is. Another interesting aspect of the mount itself is that unlike other AK and universal mounts it has no rear stop to prevent the optic from walking forward. This function is achieved by the clamp itself which has a cam that not only provides tension on the rail when mounted, but extends slightly to prevent the mount from moving forward. When the clamp is in the open position the center cam is flush with the optic rail and will slide off the front, but when in the closed or locked position the other side of the cam extends into the center cutout on the AK rail which keeps it from moving. It's not tricky to get it locked into place in the correct spot but this rail system is different than others I have seen. So far it appears to be working as expected and I have not seen any issues in the few hundred rounds I have fired through my SGL31 with this mount and optic combination.
This optic will co-witness with the rear sight leaf set on 1. Battery life is a respectable 500 hours at continuous maximum brightness. As a complete unit including side rail PK01-V weighs 21.7 oz
Out of character for most BelOMO optics, PK01-V
uses triple-A batteries (AAA) compared to the much
more common AA or type 357 watch batteries typically
You can see here that the rail is vertical against the receiver but uses a 30mm ring to position it directly over the bore.