VERMIL ARCHERY was established from an archer who love in this classical and traditional sport. Meant for the archery savvy, the VERMIL thumb ring is designed in versatile sizes to protect the archer's thumb and it fits over the end of the thumb. This modern classic ring can be used either RH or LH. Vermil Victory The Victory is a 3rd-generation ring designed in collaboration with The Cinnabar Bow. Its lip is thinner than other models, allowing for more space between the string and the palm, as well as more coverage of your thumb pad. The Victory also has a pinch-free, two-pronged guard, which gives your thumb joint more room to bend and provides a more stable hold on the string (the string rests across the dimple, which mitigates unintentional up/down rolling). Thanks The Cinnabar Bow for this good description. Measurement For choosing the size, you can measure in two dimensions like the photos we provide on listing. Please measure on the thumb knuckle and press the vernier a bit in order that the ring is able to tab from sliding over knuckle.