It's difficult when spring salmon trolling to continuously adjust your bait to follow the river bottom with just the Fish-On rod holders. The reel's cranks are right next to the top of the shelf and hard to get to resulting in many times pulling the rod out of the holder to make an adjustment. These extensions take care of that problem. I thought they were a little expensive though.
I am a pro guide. These things twist so much, you'll loose big fish. Regardless of drag setting. Supposedly they are designed to twist..right!!! Try loosing a few rods and reels and you will find alternates. There are not many that are worthwhile. The best thing to do is to encapsulate the extender in a pipe, allowing for the connections. They are no better than those aluminum rod holders (cast) by you know who claim to be to be the ultimate. ENCAPSULATE the extender!!!!