The ProPoint Neck Trainer has three LR41 button batteries powering the central laser pointer.
The battery should last about 4-6 weeks of daily use (of 5 mins) Extended use/sessions of the laser in a single session will cause the batteries to run flat much faster
When the batteries start to run low the laser pointer becomes very dim. Turning the laser off and then on again restores the full laser strength for seconds to minutes before becoming very dim again.
Replacing the batteries is possible and requires minimal equipment. It is however recommended that the batteries are changed by a professional with appropriate tools and experience.