Comfortable material. Sleeves are plenty long.  This is a light weight base layer. Bought for cycling and now wear them almost every day. I'm 5'8" and 160lbs 40.5" chest and I bought a med. Fit is generally good with a slight tightness thru the armpits. Likely the tightness is due to my weight lifter build. Overall satisfied with the garment. Patagonia base layers fit better, and cost 4 times as much.