Fixed Round Lenses Newly 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-7.2