NS Novelties Sinful O-Ring Mouth Gag. Add a spark of excitement to your play time. Adjustable O-Ring Mouth Gag comes with three interchangeable rings for a customized fit. Designed for extended use. Made of vinyl, ABS plastic and nickel-free hardware. O-Ring Mouth Gag comes with 3 interchangeable O-rings for the perfect fit. Ring is made of unbreakable plastic and the collar is fully adjustable. Say O please!!! Made of easy to clean vinyl and sporting all black nickel-free hardware.