Gamma represents a certain level of security within the Imperial Military. Specifically, it was utilized on the DS-1 Death Star Mobile Battle Station during the year 0 BBY. Its ranking fell between a few others: it was considered a lower level than both Alpha One and Beta, yet it held a higher rank than both Lambda and Rho. An example of someone with Gamma level clearance was Lieutenant Blagg, who was stationed within Detention Block AA-23 on the Death Star.