Nitecore flashlights are designed for law enforcement, hunting and tactical applications. Each of the SRT line flashlights have a smart selector ring (SSR) allowing you change your brightness, color, and different flashing modes like strobe and S.O.S. Massdrop is offering the SRT3 Defender, SRT6 Night Officer, and SRT7 Revenger flashlights all in black. The SRTs share core features, but as you scroll down, each model will have different features and varying price points.