The production code is pressed into the material itself, not printed, so it can be hard to spot.

On a reservoir:

1. Turn the reservoir so you're looking at the back.
2. Find the vertical seam on the left side.
3. Look 1–2 inches (2.5–5 cm) down from the top along that seam.

Tip: tilt the reservoir toward a light so the raised characters cast a shadow.

If you can't find it, enter "0000" on the warranty form. Your claim will still be processed.