This is a version of my pi2b/3b case designed for the new raspberry pi 4. No need for screws, glue, clips, any of that. Just pinch the side with the headphone jack when sliding the pi 4 into this case. The headphone jack will securely hold it in place.
This is designed to fit the adafruit 15 mm heatsink. You can use anything you want, if any. As long as it is no taller than 15mm, it will fit, even if it install the heatsink before sliding the pi into the case.