Brian, Thank You so much for the quick response with your information on the LPH-250. You are Awesome! In the battery compartment, it actually has a label “Do not leave batteries in the locator when not in use.” But it says nothing about the size of the batteries which you have so kindly provided me with the information. I actually bought this unit for a friend who fishes a lot who doesn’t have a Fish Locator. Thought it might be a nice inexpensive but useful Christmas Gift but I didn’t want to give it to him without batteries if I could find out what type. It didn’t have the batteries in it and didn’t have a note within the battery box as to what type it actually uses! I was just going to throw it away if I couldn’t find what type of batteries. You have provided me with that information and for that I Thank You! Stephen