Round Shader needles are characterised by a looser needle placement which results in more pigment being introduced into the skin. When working, they make it easier to build up chiaroscuro and gradation. They work well for powder eyebrows, but ones where the borders are more blurred, less defined. For contourless lips, blending and shading techniques where blurred results are desired.

RS needles are ideal for light, powdery, openwork, less detailed techniques where you want diffused effects. The 0.25mm cartridge size will leave a larger pixel than the smaller 0.18mm and 0.20mm.  

Kwadron PMU Optima 30/5 RSPT-T what's behind the symbols  

These are five 0.30mm needles of Round Shader type and Point Tapered sharpening step (2.5mm sharpening length). Cartridges designed for creating thick contours and lines, especially fills and shading due to the greater number of needles in the cartridge. The PT taper needle is double sharpened, which means that in addition to the usual sharpening, the tip of the needle itself has been further sharpened at a different, more obtuse angle. This type of sharpening means that the PT needle is not as sharp as the LT, allowing it to be inserted more gently into the skin. PT - Point taper (2.5mm double sharpened).