Standard Steel Liquid Level Gages can be used on hydraulic reservoirs, gearboxes, bearing housings, crankcases, transformers and machinery oil reservoirs.  Their use can be extended to any industrial liquid level viewing application.  Fluid enters through the cross hole in the hollow lower bolt and the gage is vented into the tank through the cross hole in the top bolt.   The length between the center of the two bolts is referred to as the centerline.  Centerlines are available from 3" to 60". 
Items
B1559-1X58

(Formerly B1559-1-S01X71), Standard Steel Liquid Level Gage, 3” Centerline, Front Mount 1/2"-20

B1556-1X39

Standard Steel Liquid Level Gage, 3” Centerline, Back Mount 1/2”-20 with Nuts

B1559-1-S04X03

Standard Steel Liquid Level Gage, 3” Centerline, Front Mount 1/2"-13

B1559-1X58

Standard Steel Liquid Level Gage, 3” Centerline, Front Mount M12 X 1.75

B1559-1X72

Standard Steel Liquid Level Gage, 4” Centerline, Front Mount 1/2"-20
Centerline N/A 3" N/A 3" N/A 3" N/A 3" N/A 4"
Mounting N/A 1/2"-20 N/A 1/2"-20 with Nuts N/A 1/2"-13 N/A M12 X 1.75 N/A 1/2"-20
Feature N/A Standard
Max Pressure N/A 125 PSI
Max Temperature N/A 300° F
Seals N/A Viton
Body Material N/A Plated Steel