Here are the pictures of 13 common valves used for air ride.
I thought it would help to see these valves side by side so you can look and see what is best for your needs.
1. SMC ½”
2. Xtreme 800 ¾”
3. DANZ ¾”
4. ASCO ½”
5. MAC DADDY ½”
6. Parker ½”
7. Xtreme 450 ½”
8. ODE ½”
9. Airlift ½”
10. SMC 3/8”
11. Airlift 3/8”
12. ASCO 3/8”
13. SMC Prototype ½”