This is a third routing metric value for this static route entry, available as an additional tiebreaker in the router's route-selection process when Metric 1 and Metric 2 don't resolve a preference between candidate routes. Admins rarely need to touch it unless they are fine-tuning route preference in a network with several overlapping static entries. Setting it to a distinct value like 10 lets this route be deprioritized behind others sharing the same first two metrics.