Many anglers will opt to bring along electronic tools for locating fish. These are not a must, but can be very beneficial. A GPS is great for marking your fishing spots for future ice fishing adventures. GPS is also helpful in navigating if you have taken a snowmobile or vehicle to your fishing location.
Flashers are sonar devices that reveal objects within your water column on a circular screen. Similar to a depth finder or fish finder, flashers can help you identify if there are fish within your fishing hole location and at what depth. A flasher should also be able to pick up your line and bait if dropped simultaneously. This helps you to see if you bait is attracting any motion (fish) under the water.
To take it a bit further, some anglers will use underwater cameras, providing a live image of what is happening under water. This helps anglers better understand fish behavior.
Video courtesy of USA Ice Fishing Team