About 2 months ago I ordered a pair of those sleeve things that protect your arms from the sun. They were cheap ones and I was skeptical and wondering why not wear a long sleeved shirt. Today I finally gave them a try and found out what the difference is. Arms are covered but there is ventilation going into the short sleeve shirt bit so the set up is cooler than just a long sleeved shirt. Temps were in the 90s while I was out riding today.