Pactiimo BASE LAYER products are EXCELLENT!! As a 5'9" 210 lbs late 60's road rider, I put in a ton of miles throughout the year (in TX, NM & CO) and always rely on Pactimo products. I wear the Men's Summit SL Base Layer (3XL) in all seasons to wick moisture and prevent chafing, and I wear the Summer Skull Cap (OS) year round to keep the sweat off my face (and provide a little warmth in winter). In addition, I LOVE the Men's Thermoregulator LS Base Layer (3XL) for rides below 55 deg and the Men's Transfer-C LS Base Layer (3XL) for rides above 55 deg. These two products (of course) provide a layer for moisture transfer, but are amazing because of how they regulate temperature. It is a tribute to the quality materials Pactimo uses that they really do keep you warm when needed and at the same time cool as needed (especially on cool days as you heat up or warm days to keep you from over heating when riding). At my age, I also like the option to wear long sleeves to protect me from the sun year round! I also recently added the Storm+ Knee Warmers (XL) to my base layer and am most impressed. (Again) in my late 60's, I've had to be careful about swollen knee tendons for several years and have cut down on miles per day and worn compression knee sleeves for added support. The Pactimo warmers have surprised me with how much better they help my knees than the sleeves, because of the quality material used! They are not as tight in a compression sense, but because they regulate heat so well they actually seem to comfort my knees through temperature (instead of just compression pressure). I've got riders (muscular) legs so I bought size XL and the silicone gripper strip definitely keeps them in place, but I find the extra air in the loose fit warms up and provides me even better knee tendon protection! Note: I could also wear a size L (and will probably try that in the summer). Bottom line, I have found Pactimo products (base layer and others) are designed well and use high quality materials that other vendors often don't, which is why they work so well for the thousands of miles I ride every year - RideOn!!