Ideal for troubleshooting fiber optic cabling problems. Flash is especially useful when showing multiple inputs and outputs. Beam mode bounces around for a few minutes after launch and isn't particularly smooth. For most debugging purposes, it doesn't matter. Since the batteries run out relatively quickly (I haven't bothered to measure the intensity over time), we usually replace the battery with a power supply, and that requires a bit of drilling and glass sawing. It would be nice if there was an external power connector. Have a good return.