Probe stations for probing with up to 4 probes (DC or RF up to 40 GHz). The TTP4 probe station (Lakeshore-Tabletop-Magnetic-Cryogenic-Probe-System) accepts a 50 mm sample with 4 probes. System is turbo-pumped to ~10^-5 Torr. Probes are viewed via high-resolution microscope (10:1 zoom, 3 micron ultimate resolution), CCD camera (still and video capture available) and color monitor. Measurement instrumentation normally kept with the system includes Agilent B1500A Device Analyzer and 4284A LCR meter for I-V measurements, capacitance measurements, and pulsed I-V measurements.Cryostat with Lakeshore controller for low temperature operation and integrated heater for 4 to 350 K temperature range with 0.05 K temperature stability. Cooling is performed with constant flow of liquid nitrogen or helium (EH&S cryogen safety training required) and the sample shield and probes are cooled via the cryostat.