The right size depends on what you’re after (vaginal or anal) and your anatomy. If you’re already used to a dildo, plug or prostate massager, compare sizes so it won’t feel like uncharted territory. Beginners usually choose S or M.
Strap-on
Size S: insertable diameter 2.7–3.0 cm, insertable length 14 cm, weight 245 g
Size M: insertable diameter 3.0–3.7 cm, insertable length 16 cm, weight 290 g
Size L: insertable diameter 3.5–4.0 cm, insertable length 17.5 cm, weight 345 g
Bulb dimensions (same for all sizes): length 7 cm, width 4.1 cm
Dildo
Size S: length 16.4 cm, diameter 3.0 cm
Size M: length 18 cm, diameter 3.3 cm
Size L: length 19 cm, diameter 3.45 cm
Size XL: length 19.8 cm, diameter 3.6 cm