Description Part Number Electrical Supply Dimensions Mass	Velocity of Sound Switches IPC-4269-W 9V Battery PP3 type Control unit: 75x100x40 Microphone: 55x110x22 0.4kg
	For the direct measurement of the velocity of sound in air using a pair of microphones and an electronic timer able to measure to 1ms. Two independent electronic switch circuits start the timer when a pulse of sound is received by the built in microphone and stop it when the sound reaches the second microphone placed a known distance from the first. A 10m lead, fitted with 4mm plugs, is supplied. Timer connections are made via 4mm colour coded sockets on the top panel. Supplied with instructions and microphone, but without battery or timer.			Instruction leaflet