Aqua Products F12 Thermal Trousers

How well is it built?

The F12 Thermal Trousers use a two-ply polyester fabric with a 100% polyester TPU membrane, and the seams are fully tape-sealed. It's a proper technical outer made for outdoor use in extreme conditions, so it should cope with the knocks and scrapes of winter fishing on the bank.

Inside, the hollowfibre filling and the cross-weave silver lining do the warming.

The silver lining is there to boost heat retention and cut heat loss, which is a neat touch on a pair of trousers at this level, and the two zipped pockets use water-resistant zips to keep small items dry.

In comparison, the Nash ZT Air Cell Trousers are built to pack small, but they're water resistant rather than waterproof, while the F12 has a full membrane and taped seams. That makes the F12 the sturdier choice for a wet winter session.

For a thermal trouser, I think the build is excellent, and 8.5 is a fair score.

Weather Protection

A 10,000mm hydrostatic head is a solid figure for showers and steady rain, and the TPU membrane and fully taped seams mean water shouldn't find a way in through the stitching.

They're windproof too, which matters as much as the rain on an exposed reservoir bank in the depths of winter.

What they won't match is the 20,000mm of the Nash ZT Helluva or the 25,000mm of the Fox RS25K Salopettes.

In prolonged heavy rain, or if you're kneeling on soaking ground for long spells, those are the safer bet, although you could always pull a waterproof over the top of the F12 on the worst days.

Breathability is 5,000 MVP, and thermal trousers always trade some breathability for warmth, so they'll run warm on a long walk to your swim.

Overall, 8.0 is fair, as they're properly waterproof for most winter days but not really built for all-day downpours or long spells kneeling in puddles.

Comfort & Fit Rating

Warmth is the F12's big strength. Hollowfibre filling gives proper insulation, and the cross-weave silver lining is there to hold on to that warmth, so they should be very cosy on a static session in a frost. Who wants to pull on two pairs of trousers before a night on the bank?

With these, the warm layer and the waterproof are the same garment.

The waistband is elasticated with a secure Velcro fastening, so it's easy to adjust over a base layer, and the hems adjust to close around your boots. The two zipped pockets are handy for keys, a phone or a lighter, and sizes run from S to 3XL.

To be fair, they're a trouser rather than a bib, so keeping the small of your back warm is down to your jacket, whereas the Fox RS25K Salopettes have a high front and back. For warmth and ease of wear, though, I think they're superb, and 8.5 reflects that.

Is it good value for money?

Value is where the F12 really makes sense. For a mid-priced pair of trousers, you get insulation, a silver heat-retaining lining, a waterproof TPU membrane, taped seams and a windproof outer, which is a lot of kit in one garment.

Buying waterproof overtrousers and a separate thermal layer would usually cost more.

The value score of 8.5 is about that combination. The Nash ZT Air Cell Trousers are built to pack into a rucksack, but they're water resistant rather than waterproof, so the F12 is the more complete winter trouser if you fish in all weathers.

The Nash ZT Helluva adds a high-cut bib and a Sherpa fleece lining, but it's built for a different job as a heavy-duty winter outer layer.

Overall, I'd recommend the F12 Thermal Trousers to carp, pike and match anglers who sit still for long spells in cold weather and want warmth and waterproofing in one pair. If you walk miles or fish mainly in summer, a lighter shell will suit you better.