I put my kuiu 145 zip t through a hell of a test this month. I loved it, I was impressed by how it didn't reak! with that said, temps went from highs in 80'sand lows in 40's to highs in low 50's and lows in the 20's and I didn't care much for the zip t as a base layer, just didn't seem to cut it for me during those early morning lows.