I don't use one but I do improvise and make one of my own. I use a small Mead, Cambridge Business notebook that's 9 1/2 x 5 3/8 with 80 sheets. The front of each page is lined like notebook paper and the back has quarter inch grid on it. It's perfect for notes, planning and keeping a list of projects. I have even made a reusable quilted cover for it to make it easy to take to meetings.