Q36.5 Base Layer Bulletproof Sleeveless

The Q36.5 Base Layer Bulletproof Sleeveless is a cold-weather mid-layer that weighs 145 g in size M. Q36.5 calls it a new extreme-cold iteration of its base layer expertise, and designs it to be worn between a traditional next-to-skin base layer and an outer shell or jacket.

The insulation is Q36.5's proprietary Air Insulation, an ultralight fleece built from brushed mesh. It is designed to trap air between layers while keeping close contact with the skin, which helps move moisture away. Q36.5 markets it as the world's lightest insulation, and the brand's claim is worth reading as marketing rather than a measured result. The fabric is 44% polyamide, 44% polypropylene and 12% elastane. The sleeveless cut keeps your arms free and avoids extra bulk under a jersey or jacket, so you can add warmth to your core without restricting movement on the bike.

Q36.5 lists a Body Temperature Stability Guarantee of +41°F for this sleeveless base layer, and it is made in Italy. It comes in Ice Grey in sizes XS through XXL. Because it is designed as a mid-layer, it works best as part of a system: a thin base layer next to the skin, this vest over it, and a jersey or shell on top. For cold winter rides, the Q36.5 base layer is a way to add warmth to your torso without switching to a heavier jacket.