Finding a replacement electrolytic capacitor

I am looking to replace this capacitor from my house thermostat.


Hello @Danny

Do you have a picture of the capacitor? Are there any markings to outside of the numbers to help identify the maker?

Markings could indicate a 100uF and 63volt. a could be a series or tolerance marking and 6D9 is likely a date/lot code.

Do you have any physical sizes on the cap? These may also be helpful in narrowing down options.