KP Polka Dot Row Counter Clicky

From Knitter's Pride:

Keep on top of your rows with this user-friendly blush pink polka-dot row counter. Just click after each completed row and you will always know exactly where you stand. No more tedious counting or marking down on nearby scraps of paper.

From Sun Dragon:

This compact row counter advances with a click, and has a brake on the side to keep your count when on the go.