These are massive single-pole, double-throw (SPDT) sealed relays. This means that when current is applied to the coil, it throws a simple changeover switch, terminating the connection from the NC contact to ground and closing the NO contact. Use them to switch high-voltage/high-current devices. This is the same relay we use in our Beefcake Relay Control Kit. https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2011-10-28 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2016-11-25 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2016-11-28 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2016-11-29 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2016-12-09 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2016-12-13 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2017-11-24 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2017-11-28 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2018-05-05 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2018-11-21 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2018-11-27 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2022-02-21 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2025-04-11 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2025-06-04 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2025-06-06 https://elecena.pl/product/2334677/relay-spdt-sealed-20a 2026-08-13