eCompressedair's model RH101 relative humidity indicator let's
you know when there is moisture in your system. 
- Indicating desiccant starts changing color from blue to clear
at 10% RH and is clear at 15% RH. The indicating desiccant will
change back to blue once you start passing dry air through it.
- Stainless steel screens at each end.
- 1/4" NPT female brass threads on each end for secure worry free
connection.
100% satisfaction guaranteed. If for any reason you are not
satisfied simply return the RHI-01 Relative Humidity Indicator or
for a full refund.
The Air Guardian AG-1 and Desiccant Snake DS20 work best with
optional Humidity Indicator.
If you have questions on how to properly select a compressed air
dryer, contact our knowledgeable customer service toll-free:
866-650-1937 or send us an email request.