A simple letterbox in east Brea.
From the posted coordinates, follow the paved path west then south around the skate park. Before you reach Lambert Road, you'll see the unpaved horse trail crossing the paved way. Head west on the horse trail. In about 500 feet you'll see four green sprinkler control covers in the ground just to the north of the horse trail. Look in the bushes between the second and third covers for your prize.
The Ikea lock-and-lock container contains a logbook, stamp, stamp pad, and some Shopkins swag. The stamp and pad are part of the cache, so please do not take them.