under this heading shall be construed to apply to amounts made available in prior appropriations Acts for the procurement of the Iron Dome and David's Sling defense systems: Provided further , That such amount is designated by the Congress as an emergency requirement pursuant to section 251(b)(2)(A)(i) of the Balanced Budget and Emergency Deficit Control Act of 1985, as amended. Research, Development, Test and Evaluation Research, Development, Test and Evaluation, Defense-Wide (Including Transfers of Funds) For an additional amount for Research, Development, Test and Evaluation, Defense-Wide , $1,350,000,000, to remain available until September 30, 2025, to respond to the attacks in Israel, of which $1,200,000,000 shall be for the Secretary of Defense to provide to the Government of Israel for the development of the Iron Beam defense system to counter short-range rocket threats: Provided , That such funds shall be transferred pursuant to an exchange of letters: Provided further , That nothing in the preceding proviso shall be construed to apply to amounts made available in prior appropriations Acts for the development of the Iron Beam defense system: Provided further , That such amounts may be transferred to Procurement, Defense-Wide for the production of such system: Provided further , That the Secretary of Defense shall notify the congressional defense committees of the details of such transfers not less than 15 days before any such transfer: Provided further , That upon a determination that all or part of the funds transferred from this appropriation are not necessary for the purposes provided under this heading, such amounts may be transferred back and merged with this appropriation: Provided further , That any transfer authority provided under this heading is in addition to any other transfer authority provided by law: Provided further , That such amount is designated by the Congress as an emergency requirement pursuant to section 251(b)(2)(A)(i) of the Balanced Budget and Emergency Deficit Control Act of