Endura's Durajak is a lightweight and packable windproof layer that'll also serve to fend off light rain. The fit is good, the material thin but tough and the hood is just about big enough to cover a helmet, but it seems quite expensive for a relatively basic item.
Made from a windproof Cordura fabric that gets a Durable Water Repellent coating to help light rain bead off it, the jacket is extremely lightweight at 116g for the small I tested. It can also be packed down into its own pocket and then it's small enough to fit in a jersey pocket or even an enduro bumbag.
It's definitely got a cycling-specific cut, with quite a high front and dropped tail that works well on the bike. The hood is just about large enough to fit over a helmet without pulling the rest of the jacket too high, though there's no way of securing it so it flaps about rather annoyingly when not being worn. The sleeves are elasticated and pretty effective at cutting out the wind though.
In addition to the unzipped front pocket that doubles as a stuff sac, there's also a zipped pocket on the other side, while the main zip gets a baffle and a chin protector to stop you pinch beard or skin when it's done right up. There's also a single reflective detail on the back - fine for when you've run out of daylight on a big ride, but it won't cut the mustard if you want to commute in it too.
It's very effective as a windproof and the DWR coating also means it does a decent job of keeping your dry in light rain, though it does start to wet out once the drizzle gets heavier and there's no seam sealing on the joins. It has proven to be pretty tough though - a few slithery crashes haven't resulted in torn elbows, which is impressive.
If you're after a no-frills, lightweight and very packable outer shell to carry as a backup then it works well - it's great for taking on marginal-looking days in British summertime - but it's fairly pricey given the limited range of use. It's good at what it does, but I'd suspect most mountain bikers would be better off with one of Endura's other keenly priced fully waterproof shells for the generally drizzly conditions of the UK.
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