The two digits in a code like 1203RL refer to the number of needles in the grouping. So in our example, 03 means there are 3 #12-diameter needles grouped together. The way they’re grouped is defined by the letters at the end of the code. RL = Round Liner, which means they’re tattoo needles meant for lining work that are grouped in a circle.

How Groupings are Arranged                   

Each grouping is arranged in a specific way in accordance to their description. RL or round liner needles are grouped together in a tight round formation. RS or round shaders are grouped together in a loose round formation. F or flats are grouped together in a line formation.  M1 or weaved magnum are grouped with 2 rows of needles in a weaved formation, so for example a 7M1 will have a bottom row of 4 and an upper row of 3. M2 or stacked magnum are grouped in the same way as M1 but are tightly stacked together hence the name stacked magnum. RM or round magnums are grouped the same way as M1 but the points are arranged in a curved arch.

Which Needle Groupings Are Used for Which Tattooing Techniques?

Which needle groupings do what?  Round liner tattoo needles and round shader tattoo needles are self-explanatory: round liners for lining and round shaders for shading. Bugpin needles (#8 or smaller diameter) are for creating smooth gradients; they can come in especially handy when you’re doing portrait work. Flats are used for areas with geometric shapes and shading. Weaved magnums are used for shading, blending and coloring large areas. Stacked magnums are used for shading, blending and coloring tighter large areas. Both can be used for lining if you turn the needle to the side. This does take a bit of skill to do, so only do it if you have practiced the technique enough or else you may end up damaging the skin. Round curve magnums are used for shading, blending and coloring large areas with less impact to the skin. The needles are made in an arch formation to better deflect the skin when it goes in and out. With a regular magnum, there is potential for the edges of the mag to dig into the skin, with a round magnum, the arch of the needle will allow you to move more freely on the skin without the risk of the edges digging in.

Reference for Needle Groupings:

RS = Round Shader needles are used for shading.

RL = Round Liner needles are used for lining.

F = Flat tattoo needles are often used for filling and shading geometric shapes.

M1 = Magnums are used for filling large spaces, blending and shading.

RM (aka CM or M1C) = Curved Magnums are easier on the skin due to their curvature.  For filling, blending and shading in delicate areas that have curvature, like the inner elbow.

M2 = Stacked Magnum tattoo needles are tighter magnums that allow you to fill in, blend and shade larger areas more quickly than standard magnums.