PrincetonCryo.com offers three different high quality automatic tank switchers, including the MVE Automated LN2 Supply Tank Swtich, the Western DS1000 Fully Automatic Changeover Manifold, and the Gordinier 2020 Liquid Nitrogen Tank Swticher. These systems enables two liquid nitrogen supply tanks to be connected to one or more cryogenic freezers. When the primary supply cylinder is exhausted, the tank switcher automatically selects liquid delivery from the auxilary cylinder and informs the user that it is time to replace the primary liquid nitrogen supply cylinder.