Castelli Pro Issue SS Base Layer

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

The SS baselayer is a super-light garment designed to operate best in temperatures in the 10-20°C range, wicking moisture away from the body quickly.

Castelli says: "The Castelli Pro Issue SS - base layers aren't only about keeping warm, the main reason for wearing a base layer is to wick moisture away from the skin and the Castelli Pro Issue SS base layer does this better than any."

Tell us some more about the technical aspects of the product?

The garment is made from 100% polyester 3D mesh fabric, with reduced seaming at the shoulders for extra comfort, the collar is wider for better aesthetics under an aero jersey and the flat waist hem sits better under shorts. It's light too at 48g for the L size.

The stitching is tight and neat, with no loose ends or obvious flaws.

I wore the baselayer numerous times in the UK within (and under) the recommended temperature range and also in 30+ degree heat in Spain and Portugal. The baselayer worked as expected, wicking sweat away quickly leaving me comfortable on the bike, even in those hot temperatures. My preference is to wear a baselayer at all times and although saturated, it never felt uncomfortable.

There have been no issues at all with the garment up to this point, but its light and very thin construction do leave it vulnerable to rips or tears should you snag it on something or you have a washing machine with a tendency to damage delicate clothing.

The material is very stretchy, so the race fit will adjust to your body shape and comfortably so, never feeling restrictive or tight anywhere.

The garment is a typical Italian (read small) sized fit, so you'll need to size up over a standard UK fit. The XL tested here was just about right, an XXL would have been perfect – I usually wear a medium UK size.

It really is featherlight at 48g for the XL, and barely more for the bigger sizes.

To the touch it is soft, and after a few minutes you don't realise it's on – the lack of seams and lower neck line translate into a very comfortable piece of kit. Even when in operation and wet with sweat there is no rubbing or feeling of being damp.

For the high performance on offer the price sits well, in between the cheaper short sleeve polyester baselayers from the likes of dhb and BTwin and the more expensive merino items which aren't always too useful in the summer months.

How easy is the product to care for? How did it respond to being washed?

I washed it multiple times in the machine on a cool wash without issue, and while away on a two-week road trip it was hand-washed almost every day with a drop of sports wash and was almost dry when wrung out – it then took minutes to actually dry when hung up, which was most useful.

Tell us how the product performed overall when used for its designed purpose

The baselayer performed perfectly on every ride, wicking moisture away and adding a little extra warmth when needed. In the heat on the Continent the extra layer didn't make me any hotter, but the transfer of sweat from the skin was good even though it was way above the intended temperature range of the garment.

Tell us what you particularly liked about the product

The low weight, comfort and performance were all notable highlights.

Tell us what you particularly disliked about the product

Sizing is a bit of a gamble, being Italian; it can be difficult to know how many sizes to go up from standard UK sizes.

Use this box to explain your score

Exceptional? Well, it's one of the best and most comfortable lightweight baselayers I have ever used, doing exactly as advertised. It's so easy to wash and dry you could use it daily if needed – a big plus if you ride lots or commute.