Embossed on the (F-Center) CHAMBERS /PAT AUG 14 1877 [ a " H " is engraved over an " N"] (R-Center) PATENT / DEC 19 1871 [ a "P" is engraved over an " T "] the embossing is very bold and clearly read. This Aqua smooth base insulator has the following issues - one ½ " chip each the right and left of the wire groove ridge (see second photograph) and a ¾ inch chip to the bottom of the base as well as a few stress lines in the base which I understand is common for this style of insulator. The insulator has small bubbles throughout the glass. I will double box this piece to insure safe delivery; current Price Guide value is 500-$600. This one can be yours for only $280.00 plus postage and optional insurance … Buy with Confidence… We do not sell altered insulators. Pay -Pal, money order, or personal check.