We purchased a unit in time for the last regular season meet of our indoor season and used it there and 2 championship meets - only wish we'd done it MUCH earlier. Best investment ever! Pleasantly surprised by the quality of construction and ease of use. We run 20+ heats of dash and 300m and without having to stop and reload every 6 heats those events go much quicker and smoother. Add in the increasing cost and difficulty of finding blanks and this will pay for itself by the end of next indoor season. We used a MegaVox portable PA that we already owned and it was plenty loud for an indoor 150m track; will probably have to bump that up a bit for outdoors - we'll see come April. Can't recommend this unit enough!