The Frostline Jacket is an ultralight narrow baffled down jacket with a weather resistant shell for alpinists and trekkers needing extra warmth and a tiny pack size.
Mountain Equipment says:
A minimalist low bulk down jacket that provides essential insulation on fast moving days. DRILITE Loft shell fabric gives impressive weather resistance for added peace of mind in exposed situations and a protective hood extends the Frostline's range further still.
Mountain Equipment's Frostline Down Jacket has a similar target audience to Rab's Microlight Alpine and Montane's Featherlight jackets. They're all designed to make a perfect layering piece for alpine climbers, or an adaptable stand-alone jacket for day to day use.
What makes the Frostline Jacket stand out is that it's a lot lighter than the others and packs down smaller too. This is down to the fact it has less fill and uses a light DRILITE Loft 20D outer fabric. Though the smaller fill means it's not as warm as others in comparison, it makes an ideal piece for those looking for something cheaper, lighter and more packable.