The Department of Energy certified Friday that a new low-yield, submarine-launched ballistic missile warhead is battle ready, the agency said Monday.

In a late-Monday press release, the agency’s semi-autonomous National Nuclear Security Administration (NNSA) said it “successfully completed the First Production Unit (FPU) of the W76-2 warhead Feb. 22 at the Pantex Plant in Amarillo, Texas.”

The W76-2 warhead is a modified version of the recently refurbished W76-1. NNSA finished building the first of these low-yield variants in late January, an agency official said Feb. 15 at sister publication Exchange Monitor’s annual

Nuclear Deterrence Summit. The agency can only declare that it has created an FPU after a post-assembly review that certifies the weapon is war-ready.

In Monday’s press release, NNSA said it would “complete the W76-2 Initial Operational Capability warhead quantity and deliver the units to the U.S Navy by the end of Fiscal Year 2019.” NNSA has not said how many W76-2 warheads it will build, or how many of those it will deliver to the Navy by the Sept. 30 end of the 2019 fiscal year.

NNSA’s W76-2 budget was $65 million in 2019. Sen. Dianne Feinstein (D-Calif.) said last year that NNSA thought it would need another $60 million for the weapon in fiscal year 2020, which begins Oct. 1. The weapon will tip Trident II-D5 missiles carried aboard Ohio-class submarines.

At the Deterrence Summit earlier this month, John Evans, NNSA’s acting assistant deputy administrator for stockpile management, said the Department of Defense wants the civilian agency to deliver all W76-2 warheads by fiscal year 2024, at the latest. Last year, in in its annual Stockpile Stewardship and Management Plan, NNSA said it would continue the W76-2 program into fiscal year 2024.