Unity Tactical SPARK, Mount, All Polymer Construction, Internal Rare Earth Magnets, Matte Finish, Black SPK-CG The Spark CAGE increases the versatility of the popular SPARK Marking Light. Molded from impact resistant polymer" it secures a single SPARK via press-fit. All four sides feature a split pass-through for standard 1" webbing. Integral rare earth magnets allow it to attach to most metal surfaces.