The following 7 needle groupings are Outlining Needles:

N1S: Single Needle: Produces a very thin line. This is used for small tattoos and detailed outlining.
N2S: Three Round Needle: Produces a medium outline.
N2TS: Tight Three Round Needle: Produces a tighter needle grouping for a finer three round line.
N4RS: Four Round Needle: Produces a medium outline just a touch thicker in diameter than the three round.
N3S: Five Round Needle: Produces a bold outline. Can be used as a shader or for filling color in very tight areas.
N3TS: Five Tight Round Needle: Produces a tighter needle grouping than the standard five round needle. Producing a slightly smaller five round line.
N7TS: Tight Seven Round Needle: Bolder outline used for larger tattoos.

The following 7 needle groupings are Coloring/Shading Needles:

N8S: Eight Round Needle: Used for coloring/shading in small to medium tattoos.
N14S: Fourteen Round Needle: Used for coloring/shading color into larger tattoos.
N4S: Four Flat Needle: Used for coloring/shading in small tattoos.
N6S: Six Flat Needle: Used for large areas of color, shading, and washes (gray shades ie: Kuro Sumi Gray Wash).
N5MS: Five Magnum Needle: Used for large areas of color, shading, and washes.*
N7MS: Seven Magnum Needle: Used for large areas of color, shading, and washes.*
N15MS: Fifteen Magnum Needle: Used for very large areas of color, shading, and washes.*
* Washes - Gray shades ie: Kuro Sumi Gray Wash (GW)