This spacer allows the use of shorter reloads in longer Pro38 casing.

You can use, for example, a P38-4G motor with reloads made for P38-3G and P38-2G motors simply adding two of this spacers inside the motor, in front of the reload.

With two of these spacers you can only have a P38-3G and a P38-6G motors to use any Pro38 reload.