Typical EIN [130] stamper embossing in a light bluish aqua. This is a plugged "A" variant and has the A on rear skirt in MAY embossed as a solid raised glass letter. Mould was probably plugged with gunk preventing glass from forming the letter properly. Has a flat base bruise to front RH side close to mouldline that affects 6 drips, a tiny micro flakelet on the WG edge by mould line and several tiny fleebites on the dometop. Displays VVNM from the plugged A side. If you want a closeup of the error, please ask. All the other A's on this insulator are perfectly formed. $6 + shipping.