Profile: Tri State Electrical Supply Inc. is a provider of electrical and electronic supplies. Our products list comprises of proximity card readers, switching power supplies, infrared thermometers, digital tally counters and robotic arms. The MK179 proximity card reader stores up to 25 tags. It has application in open doors, fences and gates. The MP25SFM 25W power megaphone has a rated power of 25W and impedance of 8 ohms. It has detachable anti-howl microphone with coiled lead, on/off switch and volume control.