The Brooks Ball Sounding Plug comes in two different sizes both with 11 balls. Insertable length of about 14.5cm(5.7”) long. It is made out of 316LVM Surgical Steel and is hollow so that fluids can pass right through it. With a ball on the top so you will not lose your grip during those intimate moments.
Small: 6mm in diameter, 156mm in length, with a 8mm ball on the top
Medium: 8mm (0.31") in diameter, 152mm in length, with a 10mm ball on the top