This will hold a 90mm (3.5") clock. It is 25 mm deep. The clock i used came with a is just a hair smaller then 90mm so a dab of super glue with keep it secure. Printed without supports. 

Link to the clock I used. https://www.amazon.com/dp/B09G9JYGV4?ref=ppx_yo2ov_dt_b_product_details&th=1

I removed the clear plastic from mine as it was cracked but i think it should still work out as there wouldn't be as much of a glare.