2510 Air Draw Check Valve Assembly, PN 41861 is now OBSOLETE - No longer Available ( as of October 2019, with valve last made about 8 years ago ).
Also called Neo Check, or AIO-ADCV-Assembly-2510
NOTE: This is NOT the Brass Inlet check valve with screen.
PN 41861 =this part goes at the end of the brine valve on a AIO system
( where the BLFC would normal fit if it was a water softener application ).
For more about AIO systems,
see this FAQ Article = AIR INJECTION OXIDIZING FILTER SYSTEM = AIO
Here is a LINK to AIO system ( AIR INJECTION OXIDIZING FILTER SYSTEM ) as sold by Nelsen Corporation = https://www.nelsencorp.com/customer/docs/SKUDocs/Nelsen-AIO-Manual.pdf