Fisher F-PULSE Video Manual Installing Batteries

The F-Pulse operates on 2 AA batteries (not included). You can use alkaline, lithium or Nickel metal hydride batteries or rechargeable lithium ion batteries. To install the batteries
Use a coin or flathead screwdriver to rotate the metal battery cap counter clockwise
Install the batteries, positive side down. Rotate the cap clockwise to close and seal. Note: Waterproofing requires a tight seal, Ensure you rotate the cap until snug.
The F-PULSE from Fisher Research Labs