Refiling leads from Prym for use with the Prym extra fine cartridge pencil in a pack of three plastic boxes , each box containing 6 pieces of leads in black, yellow and pink colors. The fine line width of 0.9mm of the refilling leads enables clean and precise marking of patterns and the clean and accurate transfer of other templates. The sturdy plastic boxes containing the leads allows for their protection and storage in an orderly maner.