The Hall C Magnets used an LM-500, but it looks like the LM-510 with dual sensor capability would be the one to use for SoLID. https://www.cryomagnetics.com/products/model-lm-510-liquid-cryogen-monitor/ Specifically LM-510-12-34 (which is 1 LHe & 1 LN2 + panel mount + voltage output) for $1,775