1650 BLFC 1.0 GPM Plastic.
This is Brine Line Flow Control is used for water softener application on the Fleck 2510 Valve.
Brine Valve Piston Assembly ( 60011 ) sold separately ( or as an assembly that includes this BLFC as separate item ).
NOTE: Residential Valves would not use this size ( 1.0 GPM flow rate ). The 0.25 GPM and 0.50 GPM are what is commonly used.
You should have a color coded label that references the size you need if replacing. And when in doubt, we recommend the 0.50 GPM ( our PN 3460010-50 ).