Like the venerable Lantern before it, this is a lot like Magnifying Glass for Survivors. Instead of an emergency damage source (or being played fast in the case of MG), the bonus effect on this one is the ability to reroll a failed test once per turn. Not a bad kicker at all if you're just looking to grind out one clue per action. I think I'd usually prefer Nautical Charts for the innate clue compression, but if you're playing a character that's not good at drawing cards, Old Compass be what you want. Synergy with Stella Clark who wants to fail tests anyway; if you fail this test, you get a free reroll AND your bonus action, nice!