"It's supposed to help amplify and transmit the same type of heat energy my body emits." She lets go of the sleeve, looking over her shoulder to him. "Only used it once, but it works, despite how old it is and the fact that it's a prototype."

Even though Rey has better control when she lights up like a roman candle, it's good to have something she can utilize that ability with and not worry about burning off all her clothes. Firo would probably be relieved to know that.