Any apparently they suck pretty bad...
The one that Airosft Austria reviewed broke multiple times during the reveiw.
... If all you're looking for is a clear scope.. buy a mid-grade real-steel scope... I have no idea why anyone bothers with airsoft scopes.. the eye relief on them is awful.
Gun Technician and Tuner
Well versed in every AEG version and all major gas and spring systems.