HEAVY: 3.8oz. Works best with properly-ported barrels. Two stainless weights, One tungsten.
HEAVY 2: 4.7oz. Works best in carbine-gas systems, and in over-gassed rack "M4geries." Also works incredibly well with properly-ported (or slightly smaller) barrels being ran suppressed. One stainless weight, Two tungstens.
HEAVY 3: 5.6oz. Works best when used in conjunction with a suppressor. We do not recommend you use this buffer without a can, as it can and most likely will cause cyclic issues. (Unless of course your barrel port is the same size as the hole in the o-zone layer over Cape Canaveral because you cheaped out on your barrel.) No stainless weights, All Tungsten.
If you came here looking for a cheap, 3.0oz., probably-Chinese "Carbine" buffer, you're on the wrong website altogether.