It measures altitude based on barometric pressure. The display is a low power liquid crystal type. These kits allow you to transmit audio from your rockets. These are interesting first payload projects, because they are easy to use and build. Holatron Systems - Safe, reliable, remote ignition of pyrotechnic devices has always posed problems.
Cables take an inordinate amount of time to lay for stage and public display pyrotechnics.
Holatron systems has designed and produced the ultimate in user programmable, digitally encoded, wireless firing systems to meet this challenge.