Humm Dinger "Double Dinger" is the "Original" Dual Vibrating Pleasure ring designed for "His & Her" Pleasure! Dual motors stimulate the genital area to create MAXIMUM PLEASURE for both partners! Motors last approximately 40 minutes + and come with batteries included, which are replace-able! There are many other "Imitators' out there, so don't be fooled by the rest...be sure to stick with "The Best" the #1 (ORIGINAL)HUMM DINGER!