Yes, the 95 means that they are 95% effective at filtering stuff out. They are respirators rather than just a mask. You can also use FFP2
Don't get the ones with the valve that opens when you breathe out though
To be precise, N95 is 95% at 0.3 micron particle size. This is the size that is hardest to filter as determined by research, lab work. An N95 will be close to 100 percent at filtering particles sized 1 micron and above. A virus of course is smaller than 0.3 micron.
The main issue is the seal, if you're using filter material of this grade and above for hours at a time, you're breathing through the gaps around the filter. If used properly, sealed completely, around 30 minutes onwards you'll start feeling suffocated. You'll pass out if you attempt a sprint. This grade and above needs mechanical ventilation to be used for hours at a time.
People mostly aren't this precise, they get the highest grade and mostly breathe through the gaps. Pretty much all the Hvac guys, engineers I know just put on a cheap china made buy 50 for a few bucks disposable where the law requires it. Not saying about its effectiveness or otherwise, but the engineering is clear cut.