The W88 nuclear warhead entered the stockpile in late 1988 and is deployed on the U.S. Navy’s Trident II D5 Submarine-Launched Ballistic Missile (SLBM) system, carried onboard Ohio-class ballistic missile submarines. Deployed for more than three decades, the W88 requires several updates to address aging issues and to maintain its current state of readiness. The W88 Alt 370 program replaces the arming, fuzing, and firing assembly; adds a lightning arrestor connector; and refreshes the conventional high explosives within the weapon.