Twin in this case means two colours, cream head followed by bright yellow running line, and I assume it also refers to the line rating. That dual rating is unusual; fly lines for single-handed rods like this one are quite clearly defined by the weight of the front 30ft of the line excluding the level tip – that’s it, no more information.

The way I understand the rating of this line, at 30ft it weighs as much as a #7 line, but thanks to the long front taper, by the time the whole head comes into play the designer believes it weighs and therefore handles more like an #8 line. It’s difficult to pursue that line of thought or examine that assumption. Fly line weights are specified for the first 30ft, beyond that point there are no boundaries. So, in theory at least I could have two lines which have the same head length and which weigh the same to 30ft but the head weights are radically different – the head of one could weigh ten times what the other weighs and still be the same line-rating.

In practice the head weights (and lengths) of weight-forward lines with the same rating do differ but not that radically. The ability to cast, and cast just reasonably well, means we use different lengths of line all the time. That means we adjust our casting to suit both the length and mass of the line. So, frankly, I see no need for the dual rating on this line.

So the 7/8 Arrowhead is a 27 yard (25 metre) line with a long front taper, short rear taper and a 39ft head (11.9m). That makes the line a little shorter than average and the head length about the 40ft norm for conventional WF lines. The profile obviously means the mass in this head is concentrated near the rod tip, when I roll cast the meatier portion of the head is in the air so I should expect this to roll and Spey cast well.

Casting overhead the extended front taper has an effect on how this loads a rod. Compared with my more conventional #7 lines this feels normal at short range. With the full head in the air to get the same sense of the rod loading with my normal lines I need to have more line in the air. Getting the Arrowhead ready to shoot for distance is a touch quicker than with my long belly lines and because similar mass is in a shorter head it is a little easier to control. This is rough and far from scientific, but despite both heads being about the same mass, I seem to cast longer with the longer head. That said the difference is not huge.

I slightly object to the length of this line – 90ft is typical so why be mean and chop off three yards? OK, it makes me feel like I hit the backing knot every time I try for a little distance, but when I reach out it means the backing knot is outside the rod tip.

Then roll casting … lovely! The profile and head length suit roll casting well, very well! Make a simple hanging D loop and the anchored line in the water is thinner and lighter than the line between my rod tip and the water surface. When I bring the rod forwards I move, I accelerate, the line close to the rod tip – that then forms a loop and peels the light thin line off the water as the loop flows forwards.

Made in the UK, the Arrowhead line feels supple, smooth and slick. The running line is thick enough that I can overhang the head by a few yards if I want to and that thickness also means longer before the running line cracks and breaks down.

Beginners and improving casters may well find the head length and the way this loads a rod makes their fishing lives easier. A pleasing roll and Spey casting line regardless of skill level. More ambitious casters (note I say caster, not angler) may find the length of the whole line a little frustrating and the head length a shade too short.