Round Penis ring to choose : 1.77 inch/45 mm - 1.96 inch/50 mm
Urethral plug total length : 3.54 inch/90 mm length
Urethral Spout diameter: 0.31 inch/ 8 mm
Material: High Quality Medical Grade Stainless Steel 316 L, no chrome plating, no rust guaranteed.
To ensure proper fit, measure the width of your cock (take that measure at the base). Once you know your diameter, you can choose the size that will fit you the most, by its size and comfort.