they don't work at all, tanks can roll right over them or just blow them up with their main gun. they were a pre-wwii design meant to stop pre-wwii tanks that didn't have suspensions and had small guns that would waste too much ammo trying to shoot through, but then those darned pesky engineers figured out how to put suspensions and bigger guns on tanks, and they became irrelevant overnight. that the hohols are using them shows their idiocy, desperation, or both. they might be effective at stopping wheeled vehicles if used right, but that's it.
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