The Sentinel Series of caches are placed along a powerline right-of-way access road, between two forest industry yards, not far from the Dam Inn Pub in South Slocan. Mount Sentinel is straight ahead.
This is one of three stand-alone caches which also contain clues for determnining the final coordinates of the fourth cache in the series.
Sentinel Series - Not So Bright
You're looking for a small bright blue lock'n'lock container.