It is important to “set” the dye so that it doesn’t fade before washing with detergent. Instructions can be found here - https://www.youtube.com/watch?v=hcZteQyEooo. I actually used the method in the video except I soaked and rinsed the hat in the washing machine. A mannequin head is especially helpful for drying. Cover it with waxed paper, then lay the hat over it. The hat measures 22 1/2” around not counting the brim. If you are not a tight crocheter a G hook would be a better option, especially for a chemo patient. The hat can be easily stretched by hand if it is too snug. BE AWARE that Lily Sugar ‘n Cream is not a soft yarn and might irritate the skin of some cancer patients. I recommend a softer yarn such as I Love This Cotton from Hobby Lobby. You will definitely need to use an H hook since the softness creates a slightly smaller stitch.