Groco parts cross reference, a part number in hand is a very helpful thing.
GROCO Strainer Parts
Looks like the part number for the strainer complete is: SA 750 S
And for the clear cylinder only: S-70 A
That is if its for the 3/4" pipe size unit.
Complete current Groco catalog:
http://www.groco.net/CATALOG/2016-CAT-LR.pdf