The novel DeFeet isn?t strictly a base layer, more like a bib that tucks inside your jersey on top of your base layer. Its compact design means it can be easily removed and tucked in a pocket or slipped on when needed.

Castelli offers protection with an extremely light, SG0.6 windproof fabric. It?s stretchy so the fit remains snug. The wind protection is excellent, it?s breathable and it?s comfortable to wear. One slight down side is it?s on the short side so the ?long-torsoed? may find it leaves a gap.

Bio Racer?s TG900 fabric has a unique fibre cross-section ? a five sided star shape as opposed to circular ? to aid with wicking.

The windproof layer, covering the top two-thirds of the front is loosely attached as it is not as stretchy as Castelli?s but it is certainly effective and just where you need it.

Verdict

DeFeet?s Un-D-Flector definitely has its uses, but you still need a base layer, so it?s not going to win here against two superb technical garments. Both work spot on, but the Bio Racer just edges out Castelli on cost and a more anatomic cut.

BioRacer KM Protect Short Sleeve undervest £42.99

Contact: Onimpex 01925 570916, www.onimpex.co.uk

DeFeet Un-D-Flector £21.99

Contact: Jim Walker 0870 752 8777, www.jimwalker.co.uk

Castelli SG0.6 Wind Shirt £45

Contact: Saddleback 01454 299965, www.saddleback.co.uk