Stroke profiles dictate how hard or soft the needle strikes the skin as well as how rapidly it retracts into the tip of the cartridge. In general, the lower the percentage, the faster the hand movement can comfortably be. Higher percentages are better for slower hand movements.

Cam sets contain all four stroke profiles in one of 2.75mm, 3.6mm or 4.2mm strokes.

• 20% is a great all-rounder, but is an outstanding liner. This was?the original cam and what makes a lot of people fall in love with Neuma 4. This cam feels the most like a coil. Very snappy needle strike with rapid recoil.
• 28% is great for black and grey shading, particularly for soft, smooth shades and gradations. A softer needle strike with a rapid recoil.
• The magic 33% has the slowest insertion speed which translates to the softest hit, with the same rapid recoil of the 20%. This cam is recommended for super soft grey shading and/or multi-pass colour layering with greatly reduced risk of trauma to the skin tissue. This cam is not recommended for lining.
• 40% is great for slower hand movements and/or solid color packing and blending. Great for colour realism. Softer needle strike with a slower recoil.