Ender-3 S1 Pro Nozzle upgrade.

Greetings, I’m totally new to 3-D printing. I have an Ender-3 S1 Pro printer and was interested in upgrading the nozzle to hardened steel or even ruby. I saw the latest YouTube post reviewing the nozzle from MicroSwiss. I purchased the MicroSwiss .4 nozzle, but when replacing it, the nozzle itself was broader than the stock brass, and the little silicon cover that overlays the nozzle and heat block didn’t quite fit. Is there a certain qualifying number ( like I’ve seen MK8) or threading or size that I need to consider when upgrading the nozzle? I realize the .4 is the nozzle aperture, it’s all the other sizes I’m not sure about. Any help would be greatly appreciated. Thanks!

It worked fine. Thank you so much!