I needed a panel mount for a small buzzer for a cable tester project. This was made to fit the CYT1008 commonly used with Arduino projects. Mounting hole size is around 16mm. Screw holes are for 3mm. Printed with PETG no supports. It's a sung fit, so don't be afraid to give it a push.

This is a link to the buzzers. https://www.amazon.com/dp/B01NCOXB2Q?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_6