Having a zero gapped blade will make your blades cut closer for sharper fade, and blend. It's important to have your clipper blades adjusted so you can blend skin fades, and skin tapers easier. The only tool you'll need is a screwdriver.
What is a zero overlap clipper?
https://www.youtube.com/watch?v=xLDtdisjcdU
What is the point of zero gapping clippers?
Zero gap is the adjusting of the two blade tips for the purpose of quicker and sharper lines when edging (lining). It also causes the difference in fade or blend guide lines lengths to be smaller. Caution should be taken using zero gapped clippers due to less room for error.