Rattlebells consist of 6mm balls with heavy metal spherical inserts imprisoned within the titanium casing. The encapsulated ball is three times havier than the titanium shell and becomes agitated with the slightest motion, causing resonance thought out the barbell. The resulting trembling effect passes through hollow shaft and percolates through the body in exciting ripples of pleasure. The balls are permantly sealed and cannot facture! Excellent for tongues, nipples and genitals. Rattlebells are also available in longer stem size (2,4mm thickness) for ampallang piercings.