There are eight different universal configurations of fittings that are offered in the market:
1. Type ‘A’ Coupler – male adapter with female NPT thread
2. Type ‘B’ Coupler – female coupler with male NPT thread
3. Type ‘C’ Coupler – female coupler with hose barb
4. Type ‘D’ Coupler – female coupler with female NPT thread
5. Type ‘E’ Coupler – male adapter with hose barb
6. Type ‘F’ Coupler – male adapter with male NPT thread
7. Type ‘PL’ Coupler – plug for female coupler
8. Type ‘CAP’ Coupler – cap for male adapter