So very used #OCXO oscillator cans from ebay.
They ware cheap and most of them should work.
Plenty of projects of mine and from friends will have nice, stable and cheap reference clocks.
And if there are duds, I get to pull one to bits or possibly learn how to repair OCXO's.

I plan to use one as a refclock for a homebrew signal generator, when I repair and re-home it to a better case.
And for a #24GHz project.

I added an HLK-LD2410C motion sensor to a Sonoff S26 smart WiFi plug running #ESPHome. The #LD2410 uses #24GHz millimeter waves and can be invisibly mounted inside the enclosure. https://lieven.kks36.be/2023/06/11/adding-ld2410-motion-sensor-to-sonoff-s26-smart-plug-running-esphome/