This handy locking row counter is very easy to use. Just press the button on top and it advances one row on the counter. To reset or correct the number shown, you just have to turn the side dials. You will find the locking mechanism is activated by a small switch on the bottom of the row counter. When you are finished with your knitting for a while, all you have to do is push the switch to lock the counter and keep your row. This is a good thing if little fingers are around. They won't help you loose your place ;o) If you like complex knitting patterns, you may want to have more than one so you can count the rows for different pattern repeats at the same time.  If you are a machine knitter, you can use it as an extra row counter. A very reasonable price for this great gadget.