should body, head, face (face is optional), I don't want anything fancy, and my skin isn't made out of paper, what should I look for, like batteries, the type of clipper, rpm or other numbers etc..
(I don't want brands or models, but specifics I should look for)
The only advice I have as someone who has trimmed and shaved for many many years is to get two razors; one should be a real "close shave" kinda razor and one should be a beard trimmer. Basically any area you want real smooth go over it with the beard trimmer first to get the hairs down low and short, and then go over it again with the actual razor. This has always helped me get the closest shave especially if you don't keep up on it. If you do it every day then you may not need the beard trimmer but I think it helps.
Anyway I hope this helps. I will say basically all razors suck these days. I replaced my cheapo one recently with one of those ridiculously expensive ones and honestly the cheapo one did a better job. So basically they must all be totally shit.