A departure from the more usual down or synthetic insulation fills, the Piz Boe midlayer uses a lightweight layer of merino wool stuffed between a Pertex outer fabric and a soft and supple inner. Elasticated fabric underarm panels provide breathability and freedom of movement, while elastic cuffs and insulated hood add protection from the elements.
The Piz Boe is built for demanding ski tourers, and this design principle is echoed in its low weight of 360g and slim, ergonomic fit.
In use the Pertex outer fabric is one of the most breathable available while still managing to block out wind and resist water. The Swisswool Light Tec merino fill weighs just 60 g/m2 and although down is a better insulator, the merino fill will still insulate to an extent when wet.
The merino theme is continued in the elastic underarm panels making them feel highly breathable and staving off pongs as well as providing superb freedom of movement. If it does get too hot, underarm ventilation zips help to dump heat rapidly.
The tight fitting hood fits nicely under a helmet, can be adjusted with one hand and provides a decent haven of extra warmth when required. Both the hem and cuffs are lightly elasticated which helps keep the warmth in while not feeling too restrictive.
In summary, Ortovox has hit the sweet spot with the performance of this mid-layer. At £220 it's towards the top of the price scale but if you're serious about your mountain pursuits we would heartily recommend taking a look at the Piz Boe.
