I used the Triosharpener GRIP. It did not work for the color pencil. It didnt fit! I had to use my old tri from the 80's and that worked. But I am still not happy with it. These pencil's are not standard. They are wider than other color pencils. Drives ... Beautiful portrait work! http://www.kerrysimmonsart.com/ This week, Q&A!! 8x10, albrecht durer watercolor pencils, gray mat board.