3" NPSH Male x 4" NPT Male Adapter Aluminum HA25NYFD15F You don't need couplings because

You don't need couplings because you just want to clamp your hose onto a pipe or shank outlet

5" fire hose will give you far more water flow than a standard 1

If the two ends of a coupling are different (e

This will increase your 2

3" NPSH Male x 4" NPT Male Adapter Aluminum HA25NYFD15F You don't need couplings becauseSpecifications Male Side 1 3 NPSH Male (National Pipe Straight Hose) Male Side 2 4 NPT Male (National Pipe Tapered) Working Pressure 300PSI Max Test Pressure 1000PSI Max Material T 6061 Aluminum (Aircraft Grade) Finishing Anodized (99. 9% Lead Free) NFPA Standards 1963, 4. 12, 5. 1 5. 6. 4 (Corrosion Resistance) Military Standards MIL A 8625 Type III, Class 1 Industrial Standards International ASTM B221 UL Labs Standards 236 8. 1 Through 8. 2 USDA