Quality crafted surgical steel and quite a sexy piece at that. Comes with a padlock to ensure no escaping. This piece is definately a conversation piece to say the least ... This piece comes beautifully presented in a black velvet pouch making it an stunning gift! HEAVY DUTY STEEL The diameter of the ball ring have 5 Sizes: 38 mm/1.5 inch (S) 40 mm/1.6 inch (M)42 mm/1.7 inch (L) 45 mm/1.8 inch (XL) 50 mm/2.0 inch (XXL) heavy Duty