I really like this and it is challenging.  However many wrote how they liked using the Sharpie Utlra Fine pens, so I got the 24 pack since Mindwave has a 24 pack but read the reviews for them and and glad I got the Sharpie's but NO color names on the pens :(.  And would have given this five stars but you only need about 9-10 colors!!  They do give you empty pages of ones you have done previous with the numbers, so you can be really creative by yourself.  Maybe, but PLEASE Mindwave do books with far more colors!!  Like to match your pen set or equal?!