Features:

Weighs 4.6 oz

Contains two tungsten weights and one steel weight

Standard carbine length buffer

Aluminum exterior

Fits AR-15 and M16 carbine buffer tubes

Use with standard AR-15/M16 carbine buffer springs

H3 is 5.4 oz

Benefits:

Increased weight allows for more reliable function in rifles with shorter gas systems

Heavier weight reduces bolt bounce in full auto fire

Increased weight also softens recoil

4.6 oz weight also allows for a longer dwell time slowing down the cycling of the rifle

H3 is 5.4 oz

Link to parts manufacturer