Our Double O Kegel Balls are built for pleasure and to strengthen your pelvic muscles, which leads to stronger, more intense orgasms! Made of silky smooth, body safe ABS plastic, each ball contains a weighted bead that cause organic vibrations with your movement, stimulating and massaging you. As a tool to bring strength to your pelvic muscles, simply insert both silky soft beads and use your pelvic muscles to hold them in place. Try using them while doing yoga, or while in the shower or around the house. Women report after a few weeks of dedicated use they feel noticeably stronger. Includes Comprehensive 16 page user manual written by renowned sex educator Ducky Doolittle For Pleasure & Orgasmic Strength Smooth Satin Finish Emits Vibrations via Movement of an Inner Bearing Includes detailed User Manual Measures: 1.3 Inch Diameter Weighs: 0.8 Oz.