I used "black", but there are many dark colors on the roofing material, I purchased additional white. There is no dissatisfaction except that "Holder part is delicate, there is only strength less than office supplies, and it breaks easily". Coco should be covered with a metal holder.
In magic, there are things that can not be used in a day if it is the worst because of the life span of the pen tip than the ink, but this product does not have it. Especially when you need to snag onto a dusty concrete surface at the site, you can use it even in situations where you hesitate in magic. There is no core breaking and durability is sufficient, but on a wet metal surface, it is not as strong as magic, but it can not deny it is still difficult to write. There is also preparation for replacement core, it can be continuously used because it is inexpensive.