Basically, a remote explosive device in a form of a red rubber duck! Unlike actual remote explosives that will immediately raise suspicion when seen, these will make your targets go, "Huh?" Obviously, the element of surprise is there for your advantage.
Chuck one where you need to, the curious victim will investigate the shiny red toy, only to be blown to pieces when you press the button!
(Also, very useful in speed runs if those are your thing.)