What does 1 Samuel 6:18 mean?

The gold rats matched the number of Philistine towns ruled by the five leaders, both fortified cities and country villages. The big rock where they set the Ark is still there in Joshua's field at Beth Shemesh as a reminder. 1 Samuel 6:18 - Modern Text Bible

(The gold rats represent all the Philistine towns, and the rock becomes a landmark for this event.)