The paper describes the design, construction and performance of a continuous-wave spectrometer for use at temperatures between 77K and 80 degrees C. The limiting sensitivity for chlorine resonances with narrow lines is 1 mu mol and compounds of molar volume up to 10⁴ cm³ can be studied. The corresponding figures for nitrogen resonances are 300 mu mol and 10³ cm³. The continuous tuning range with a single coil is 2.5:1 and the resolution is a few PPM. It uses bisymmetric Zeeman modulation, there are no critical adjustments and no elaborate extra equipment is required.