The Type 1 and Type 2 NoJam followers are most preferred by those using shotguns with additional capacity magazine tubes. In other words tubes that are capable of holding more than 5 rounds. They both have a bit of a tail on them that allows the spring to be well ordered and centered as it becomes compressed while loading the magazine tube. 

The Type 3 NoJam followers are most used by those using shotguns with standard length magazine tubes. Hunting guns, sporting clays guns, and general purpose all around shotguns can take advantage of the almost friction free loading and smooth action cycling that only S&J Hardware NoJam followers can offer.

They offer almost friction free loading and smooth action cycling are the two main answers. If you shoot shotguns much you have had it happen to you. You have had a hard time getting the magazine tube loaded. Could have been in the duck blind, pheasant field, or at the range. It was damn hard to get that next shell in the magazine tube even though there was space in there. Factory followers bind. Dirt, powder fouling, gummy cleaning residue, some how end up in the magazine tube making the factory follower bind and stick. S&J Hardware NoJam followers don't stick or hang up.

S&J Hardware NoJam followers all share these common features:
They are milled from a solid block of DuPont Delrin. DuPont Delrin is self-lubricating because of its low coefficient friction. In addition it is impervious to most solvents. NoJam followers have been engineered to slide smoothly even if they encounter dirt, debris, or a rough spot and have relief grooves so they fit in dimpled magazine tubes. These relief grooves allow NoJam followers to pass over dirt and debris.NoJam followers retain their qualities at all temperature extremes. If you absolutely need to get your shotgun loaded and need the action to cycle smoothly you need a NoJam follower.