Crucial is a good resource to start with. https://www.crucial.com/ Their website has feature similar to car parts shops. You need to know the exact model of your device. That information is usually on the underside of a laptop or the back of your PC tower. Type that into their search for the SSD or hard drive and it will let you know which drive is 100% guaranteed compatible with your device.
Otherwise, it may take a little digging for an older device, but Lenovo has all their product manuals on line. Other manufacturers usually do as well. Those will often say what kind of drive your device has. It's a little less reliable for exactness however, because many of the manuals cover a number of the models variants as well. But it is likey to point you in the right direction as it did for me.
The reason the screw is getting stripped is because it's a JIS #1 screw. JIS screws are not Phillips head screws, they are a Japanese variant and the screw drivers are not interchangeable with Phillips head screwdrivers. Just be careful to make sure you are using a JIS #1 screwdriver or the screw will strip…Just learned this the hard way. I'm still hoping I can get it out…here I come Lowes.
And don't worry Aidan you're guide is not the reason I made this mistake. Almost no other guides mention this. I've come across 60+ year olds that just realized the difference while on my search to figure this out. In fact, the error was what may have save my butt (knowing it was a problem made me be as careful as I could with what I had).