The 890 two-sided probe is used with a surface resistance meter to take volume resistance, point-to-point resistance, surface resistance, and resistance-to-ground measurements. The 890 probe's unique two-sized design combines a concentric ring probe and a cylindrical disk probe into one easy-to-use testing device. The probe is made with conductive plastic containing silver particles. The 890 Probe Kit includes a stainless steel plate, an insulative plate, a blue guard cord, and a conductive carrying case.