The first difference between analog flashers and digital sonar units is that flashers present the water column in a circular dial configuration, with depths arranged like a clock. Generally, flashers operate and display fish and lure movements in near real-time, while digital sonar may present a barely perceptible lag. Analog flashers, however, don't allow for split-screen sonar/map viewing and can't offer quite the precision of digital technology, relative to target separation. Analog flashers are also perceived to be slightly more reliable, especially in sub-zero temperatures. That said, modern digital sonar units have become increasingly dependable, employing special heated LCDs to keep the liquid crystals functioning in all conditions.