Print out on card stock. Laminate and cut out each rectangle. Use with students who are beginning to write numbers and verbally count. Have them use a dry erase marker that way they can use these over and over. If you would like to, use laundry pins and mark 1-6 on them. Model placing the 1 pin on the 1 rectangle. Place the 2 pin the 2 and so on and so forth.
I have used mycutegraphics.com for this.