Measure thumb circumference:
S/M: ~6cm
L/XL: ~7cm
Recommended for convenience and protection. As a novice, I use the thumb sleeve for the last warm up set or two, plus my single “heavy” work set of deadlifts. Removing sleeves, chalking thumbs (with rest of hands) before work set helps keep them in place through the work set. Excellent service, so 5 stars.
Great product, I typically use hook grip when doing heavy deadlifts which has lead to some blisters and tears on the inside of my thumbs. These have definitely made an impact and are a must have if you have suffered like I have.