Hegar Sounds are now available individually, for those who would like to try just one instead of purchasing a whole set. The Hegar Sound is a urethral dilator with each end a slightly different diameter. The purpose of the sound is to gradually and gently enlarge the urethra using a smooth metal shaft that is inserted into the penis. Urethral play can be an adventurous new facet of your medical fetish or BDSM scene. Measurements 8 inches long, one end is 6mm e or approximately 0.3 inch in diameter, opposite end is 5mm e or approximately 0.27 inch in diameter. Material Chrome Plated Brass. Warning: This is a NEW item that is not in retail packaging, usually a plain box, wrapped in plastic or a poly bag.