Powerheads are a very controversial subject in the spearfishing community. We do not condone hunting with power heads, however we do condone protecting yourself. These power heads are CNC machined from Delrin and precision-made to fit the most popular shaft sizes available. They are designed to accept a .223 Cal round (we do not supply the rounds). They do not have a firing pin or any moving parts to fail. Put fingernail polish around the bullet and the primer before inserting. This keeps your rounds watertight. You only load them once and can only fire them once. They stay together until you use them, then they will disintegrate upon impact. Please watch our YouTube instructional video before attempting to use these.