How do you interpret the result?
If the tip of the tool (the right-hand part) does not go beyond the line above the "OK" sign, then your chain and cassette are in perfect running order.
If you press the right-hand tip of the tool in between the 2 lines of the "1", then you need to change your chain.
If you press the right-hand point of the tool beyond the line at the start of part "2", then you need to change your chain and cassette or freewheel.
