Shoulder Strap: Look on the bottom of the camera toward the right, as you face the front of it. This is where the 12 volt port was for my Wild View Ez Cam. It had a rubber plug in the hole. You can check your manual diagram or if you have misplaced the manual, go to Wild View website, select your camera model and download the manual. If you have a retired power supply from an Attari etc. with a barrel type plug, cut off the transformer (the block piece that plugs into the wall outlet and discard it). One wire should have either a white or dotted tracer. The other wire will be black. Using a multimeter to check: with the meter set at continuity, put one meter lead into the center of the barrel plug and touch the other meter lead to the wire with the tracer. This should show continuity. Label this wire end "+" as this will go to the positive post of your 12volt battery. As a word of caution: 1)make sure your camera is turned off when hooking up the external battery and 2)do not reverse the positive or negative wires when hooking up the battery or you will fry the external port system of the camera. Even though your camera only takes 4 "C" batteries which will total 6 volt, it is wired for the 12 volt port. Your computer card in the camera will have a resistor which reduces the incoming voltage to 6 volt. Hope this helps.