G
"G"' insulators have yet to be attributed to a specific manufacturer.
U-236's embossed  "G" on the dome
U 229
No Name U 229A that can be, without a doubt, attributed to "G" production.
Characteristics:

Color(s)
--- a distinctive pumpkin pie brownish orange, dark reddish brown

Pinhole(s)
--- glazed except for the dark red/brown

Pinhole Top(s)
--- domed

Fire Rested
--- skirt

Wet/Dry Processed
--- dry

Marking(s)
--- embossed "G" on crown/dome