Where the number is
The part number is printed or cast on the part itself, on its box, and in the dealer invoice. Toyota numbers look like 43512-0K090; Nissan like 40206-4JA0A.
Dashes and spaces do not matter
Search on this site ignores dashes and spaces, so 435120K090 finds the same part. If a number was superseded, the listing shows “Replaces” with the old number.
Cross references
Aftermarket brands publish which OE number their part replaces. The “Fitment and cross-reference” tab lists them, with prices, so you can compare genuine and aftermarket on one page.
