The flip lets the Doctor examine the naked eye without the patient having to remove the set from the head. Designed with LED bulbs. Lightweight. Frenzel Lenses made of light plastic materials including the lenses, resulting in a comfortable, easy-to-use system. The Frenzels stay in place well during Hallpike and Headshake tests. Safe. - Frenzel Lenses are powered by low voltage batteries, eliminating the possibility of electrical shock. Battery pack included. Product ID. FL-7FlipLED