The Naval Sea Systems Command (NAVSEA) intends to modify an existing contract with Ultra Maritime in Braintree, MA, to increase its maximum value for the Acoustic Device Countermeasure (ADC) MK 3/4 system, which enhances submarine survivability. This modification will be awarded without full competition, as Ultra is the only available source to avoid unacceptable schedule delays. This is a pre-solicitation notice for informational purposes only, not a request for proposals, and no solicitation documents are available. Interested parties may submit a capability statement demonstrating their technical expertise by the specified closing time via email to the provided contacts. No budget amount or performance location is specified in the notice.