Are you one of those people who uses a 30 rounder mag as a monopod sort of thing when shooting from the bench?
Well if so thing might be for you.
It features a rounded body for pitch changes but is squared off to limit roll
Requires no perminant mods to your mags, it simply replaces the bottom plate on a p mag
Designed for M2 PMAGS but also can be jammed onto a M3 mag
Adds about 1.5" to over all mag length
Solid construction so it won't break
Does not allow additional mag capacity