You get a set of two row counters in different sizes.

These row counters are the kind you put at the end of one of your single-pointed needles/jumper needles. Each time you have knitted a row, turn the white ring to keep track of the number of rows you have done. One side of the row counter counts ones, and the other counts tens, letting you count all the way up to 99. You could also use it to keep track of the number of increases, design repeats, or any other countable thing you can imagine. The little blue row counter fits needles up to 5,5 mm (US 9), and the red one fits needles up to 7,0 mm (US N/A). On very small needle sizes, the row counters won’t be able to get a firm grip.