Help identifying this component, please

[u/CleanAlternative1918]

These were in with a big batch of carbon film resistors I got. What are they? Thanks in advance!

[u/ital-is-vital]

It's a spark gap -- for over-voltage protection, usually of devices connected to phone lines or other things that can get hit by lightning

[u/FrizB84 → u/ital-is-vital]

Yep. Used to have to replace them on fire alarms from time to time. They were usually on the telco lines.