Buck Knives Retractable Diamond Pocket Sharpener (Sharpens Serrated/Non-serrated Blades + Fish Hooks) 97070

I love these things. I've had probably a dozen or so over the years, and these are actually better made now than they used to be. Watch out for cheap alternatives that look similar. I'm a fanatic for being sure all of my trolling hooks are super sharp before I send them off the back of the boat, and having one of these in my shirt pocket makes that easy to do. Buy a handful. You won't regret it.