Glad I went w large women size based on sizing reviews, 5ft 9in 160 lbs with broad muscular swimmer back, even tho measurements were on ML spectrum. Fits great over trisuit with decent compression, armholes generous for freedom to stroke but covers edges of trisuit top nicely to reduce drag. Bonded seams and water resilience add to reduced drag feeling. Zipper very cool,, locks when pull is down and when up zipper pulls apart... had to practice few times but better than having long lanyard tucked in back or dragging and tangling around arm. Expensive but fabric, comfortable compression, dragless seams, trisuit coverage and zipper combined appear make it a good value for anyone wantinting to shave off swim and transition time. Only worn once for practice, eager to race in it and to see how durable over time.