3.5" NPT Female x 4" NH (NST) Male Adapter Aluminum DMH40F40F They are used to fit

They are used to fit straight / tapered end hose or pipes

5" NYFD Female x 2

5" NH/NST aluminum couplings

5" NST (NH) Male Pin Lug Adapter

and you can unhook them at 50

3.5" NPT Female x 4" NH (NST) Male Adapter Aluminum DMH40F40F They are used to fitSpecifications Female Side 1 3. 5 NPT Female (National Pipe Tapered) Male Side 2 4 NH (NST) Male (National Hose National Standard Thread) 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