I was searching for a light weight, warm technical mid-layer down jacket for my girlfriend. She wanted the new Rab Zero G jacket (which I have), but Rab unfortunately only makes it for men at the moment. The next best option was the Rab Electron Hooded Down Jacket. I initially considered the Arc'teryx Alpha AR, but it didn't have waist drawcords and is not as durable and hydrophobic as the Rab Electron. Arc'teryx's Alpha SV has those attributes, but was heavier than we wanted for a mid-layer. The Rab Electron Hooded Jacket fits her perfectly in XS (5'2, athletic climber build), keeps her warm, fits under her Arc'teryx shell, and is durable enough to act as a stand-alone jacket. It also packs down nicely in it's own bag and can be easily clipped to the back of her harness while ice climbing. On cold days, she usually adds an additional belay parka (Arc'teryx Dually Belay) over this system for extra warmth. I would highly recommend this jacket.