Baitrunner is a recognised trade mark of the multinational company  Shimano. Many other manufacturers have now copied the concept of the bait runner reels, but none have quite achieved the same success. These variations should really be decribed as free spool reels and not as bait runner reels.

The bait runner reel permits the angler to set up his rod such that when a fish takes the bait , it is able to take line with very little resistance from the reel. There is no danger of a large fish taking the bait and pulling the rod off of the rod rests. The angler can instantly re-engage the normal clutch mechanism so that he can strike and land the fish in the normal way.

On a normal fixed spool reel there is an adjustable clutch with either rear or front adjustment that permits the angler to adjust the tension required before the line is permitted to be released from the reel while the bail arm is still engaged. When playing large fighting fish, this prevents the line from breaking. Even the cheap Shimano reels are a great improvement on the standard technology.

With the bait runner reel a second clutch permits the free release of line with the bail arm engaged. A small lever engages and disengages this additional clutch, and it can also be disengaged by a small turn of the reel handle.
This means that the fish can take the bait and then run with it feeling very little drag, hence the name Bait-Runner.

In operation having put the rod in the rests with the alarm set as normal. The baitrunner clutch lever is switched, permitting line to be released At a rate determined by the baitrunner clutch setting. This means that fish may now take the bait and run without either feeling line tension, and the danger of the rod being pulled into the water by the line tension is avoided. The angler having been alerted by the alarm simply picks up the rod and turns off the baitrunner clutch by either turning the reel handle, or flipping the baitrunner lever. He is then able to strike and play the fish as normal.

The baitrunner tension, and the normal clutch tension can be set independently to suit conditions.

When first using the Shimano baitrunners it would be advisable to not set it in a completely freeline  mode, but to always have a little resistance set on the baitrunner clutch. When set completely freeline it is likely that the new user will forget to re-engage before striking. This can result in a real birdsnest tangle if there is no clutch tension set.