A good base layer should, at the very least, do two things: it should provide next-to-skin comfort and keep you dry. The Gore Bike Wear Short-Sleeve Base Layer offers these benefits when worn under bib straps, a jersey, a jacket -- you name it. And its reasonable price tag shows that Gore Bike Wear believes that dropping a hundred dollars or more for a base layer isn't necessary to enjoy some added comfort.Sure, your jersey is made of sweat-wicking fabrics, but that doesn't mean it won't get clammy on hot, humid days when you're really working. The Short-Sleeve Base Layer is made of a thin and soft polypropylene/elastane blend that gives you added moisture management. Specifically, its push-pull effect draws perspiration away from the skin and to the external layer of the fabric, where it can evaporate. You won't find many seams on this base layer, but the ones you will find are flat-locked to minimize friction. The back is extra-long to provide full coverage over your lumbar region. The Gore Bike Wear WS Short-Sleeve Base Layer is tight-fitting and comes in sizes Small through XX-Large. It's available in Black or White.