SEPCO
Sepco ML4002 Graphite Packing Ring 1016572 (Pack of 6)
You will find U-blox works well with Raspberry Pi for prototypes.
SEPCO ML4002 (38332-0) 3/4 Packing Ring (LOT of 2!)
A nice touch on the WR-A212 (SA) is the labeled fuse holder for quick swaps.
SEPCO ML4002 BRAIDED FLEXIBLE GRAPHITE PACKING SIZE 3/8", NOS.
What stands out about LAUCO is the value for the price paid.