Bottom gives you 3 shots and timer extens on precision kills. Top adds time and refunds bullets on a kill, but has a 30 meter range before damage falloff. At 45-50 meters it takes 2 shots for a non super guardian with 5 resilience. Base time for both is around 10-12 seconds, by comparison, base time for most roam supers is 15-17 seconds and kills arnt required to extend the timer