Icebreaker's SS Circuit jersey passes over common synthetic fabrics in favor of a nearly 100 percent New Zealand-sourced merino wool, supplemented with just a bit of Lycra for stretch and shape retention. The natural fibers lend a distinctly cozier feel and less of a 'superhero sheen' than most jerseys.
The SS Circuit is roughly 30 percent heavier than most of the synthetic jerseys in our stable but that's unnoticeable in everyday riding. That changes if you get caught in the rain or are especially prodigious at sweating, however, as the fibers absorb quite a bit of moisture. We generally paid more attention to the SS Circuit's quality cut, though. Besides, most racers who care about those weight issues are likely to have their own team kits, anyway.
Icebreaker stitch the jersey with a mostly form-fitting pattern that's fairly snug aside from a little sag when in the drops. Though not especially aero, it's comfortable and functional, and certainly not in the least bit restrictive – exactly what most casual riders are looking for in a cycling top. As expected, the jersey is comfortable across a wide range of weather conditions – from damp and cool to warm and dry – without having to add or subtract base layers of various weights.
We wouldn't recommend the SS Circuit for truly hot conditions, however. While the merino wool knit breathes well, it's just too thick for those days when you're looking to wear as little as possible and it doesn't wick perspiration nearly as efficiently as good synthetics. Add in some humidity on top of that heat and you quickly start to feel a bit stifled.
Icebreaker fit the SS Circuit with a trio of rear pockets for storage, with the outer bays angled for easier access. The left side also sports a smaller pocket and wire pass-through perfectly sized for a smaller iPod while the right side is supplemented with an additional zippered compartment for valuables. Overall capacity is very good but Icebreaker have perhaps gone a bit too far with the downsized center bay – it's too small to reach your hand (or fit most jackets) into but too big to snugly fit a mini-pump.
Observers will no doubt comment on the SS Circuit's derivative styling, even down to the circular zipper pull on the rear pocket. That's not to say Icebreaker's rendition isn't appealing – we actually find it quite fetching. Durability has been excellent. We haven't put the SS Circuit through the dryer – very much a no-no for all-wool garments – but it's held up to countless machine washings since May with no pilling or other ill effects.