Qty 1 - #0 Phillips precision screwdriver
Qty 2 - CR2025 Lithium batteries (available at all major stores)
Step 1 - Release buckle and allow the collar to lay flat.
Step 2 - Slide the battery unit to the side and pull out of leash about 1 inch total.
Step 3 - Using the #0 screwdriver, remove all 4 screws on the battery case
Step 4 - Gently slide old used batteries from the cage. (NOTE: DO NOT use a metal tool for this step)
Step 5 - Stack two new CR2025 batteries with the positive side facing upward and slide them gently into the battery cage
Step 6 - Replace battery cage cover and verify it is seated correctly
Step 7 - Using the #0 screwdriver, screw the 4 screws back into the battery cage
Step 8 - Verify the unit lights up correctly, then slide the battery unit back into the leash.
If you have any issues with this process, Contact Us. (We would be glad to help you)