USCG-approved, manually operated, single D-cell strobe offers as much as three miles of visibility!It's waterproof to 12' and operates up to 30 hours. Features a pressurized Xenon gas bulb, rust-proof ABS case and stainless steel lock pin for PFD attachment. Requires one D-cell battery, sold separately. Light Type: Strobe Maximum Range of Visibility: up to three miles Battery Type: D-cell (sold separately) Battery Life: 8-30 hours Case Material: ABS Dimensions: 4-1/4"L x 2"dia. Attachment Method: Stainless steel lock pin Type Approval: USCG