Thank you for commenting!
Although Vaisala does not manufacture an actual “level sensor”, The HMT140 can monitor analog and contact signals from third party sensors. You would need to buy the LN2 level sensor – and then the signal goes to the HMT140 and gives an alarm for low levels. To learn more, please contact your local Vaisala application engineer - you can find them here: https://www.vaisala.com/en/contact-us