Ultralight at just 86g, the Slipstream packs very small into a separate bag and easily stows in a jersey pocket.
It’s very good at keeping the chill off your chest without overheating you. We were comfortable – in that respect at least – for a steep 10-minute climb and the speedy descent on the other side without needing to adjust the zip.
Our large sample came up quite big, and the cut is completely square so it’s long in the front and gets a bit ﬂappy at speed. As for keeping out the elements, it’s certainly windproof, but unfortunately it’s not waterproof.