Cheap SMB shorting dust-covers or dummy loads?

[Pack34]

I'm using a small SMB connector for an interlock and wanted to source some cheap dust-covers or dummy loads for when the interlock is not needed.

I'm looking for more of a dust-cap like you see for BNC connectors. Those seem to be easy to find any only cost a couple dollars. Some of the dummy loads I've been able to find for SMB connectors are upwards of $20.

Does anyone know of a place to buy these cheaply? I just need to ground the signal.