2PCS Vacuum Cupping Multi-Functional Rotary Magnetic Therapy Cupping Massage Device Magnetic Therapy Cupping Device Physiotherapy Cupping Nipple Sucker Massage (3cm)

They worked well for the first two uses, then promptly broke. If you untwist the knobs (counterclockwise) once they are at the top, the retaining clips pro off and the knob falls apart. These are no longer useable. Will get a higher quality product. Hope the company can fix their design flaw