SpheroTungsten in a density of 15 grams/cc.  This shot has been used by a major U.S. manufacturer in their finest heavy weight loads.

SpheroTungsten Maximum in a density of 18 grams/cc

BPX Devastator Tin-Plated Tungsten Shot is now available in #1, 4, 5, 6. The finest waterfowler shot on the planet (2-1/2 lb. bottle only)