The kit comes with everything you need to convert your gun to a roller when maximum power and range are required, aside from the gun rubber. You will also need to drill the handle to widen the hole for the pin.

Unlike most other rollers the Rob Allen version comes with ceramic discs for enhanced durability.

This increase in power of the Rob Allen Tuna Roller Gun allows for more penetration on the target and more accuracy and range of your shot.

Another advantage to roller guns is the way the have less recall due the roller counter acting the rubber releasing both ways.