A stabilized, finned slug with a deep hollow core for loading combustible materials. The exploder round has curved finns in the rear of the slug for stability. D.O.T. regulations require that the "Exploder" hollow cavity be shipped unloaded. This allows you to load the cavity yourself, safely with no tools required. complete instructions included. 23/4'' round. The sale or shipment of this ammo is also restricted to: All of CA, All of FL, All of IA.