Automag classic vs Automagield

[RenegadeSniper]

What are the differences between an automag 68 classic and a automag field marker?

[guseppe16]

If I remember correctly, the valves stamped "Field Rental" have a limited maximum velocity around 260 fps. I think that's the only difference. This is due to the powertube diameter being less than a normal Classic valve. This also means it won't accept the level 10 bolt without drilling the powertube to the proper diameter.