DoubleTap Equalizer ammo uses two projectiles in a single cartridge to deliver a devastating blow on the target: both game animals and criminal attackers. The projectiles are of different design, each wounding the target in different manners.
The exposed bullet is a standard jacketed hollowpoint. The second projectile is stacked under the hollowpoint and is solid lead. Exact configuration of the second projectile – ball or wadcutter type bullet – depends on the load. There are some great photos of these cartridges and bullets at the IAA forum here.