I love to recommend these to parents with young children who like to press a little too hard! The 6 mm core is so thick it is almost impossible to break and they seem to last forever! Older artists will love the way you can cover large areas quickly and their soft smooth bright colors! Same wonderful pencils as the 3mm and 4mm colored pencils, just thicker to last longer and hold up to lots of abuse! Rated 5 on the scale of 10. Set of 12 colors.