From Insulator Wiki (Wikilator)
Type: Supply House
Location: Boston, MA
Manufacturer: Possibly Electrical Glass Corporation, Cape Cod, MA.
Production Dates: circa 1889-1900
The Pettingell-Andrews Company was a distributor of electrical goods and wiring supplies in Boston from 1888 through 1927, when they were acquired by General Electric on 1/31/2008</ref>
The original company name was "F.E. Pettingell & Company", but in 1889 this was changed to "Pettingell-Andrews & Company".
Their office address during 1888 and 1889 was 167 Congress Street, Somerville, Massachusetts, and in 1890 the firm moved to 196 Summer Street, Boston. Through 1927 the organization changed its office location in Boston on several occasions. During most of the company's existence, the Pettingell-Andrews Company was a prominent distributor of all manner of General Electric Company products.
All insulators manufactured on special order for this company are lettered "PETTINGELL-ANDREWS CO BOSTON" around the skirt. These are CD 134's, identical in appearance to the Diamond-P and C.E.L.CO. insulators, and have unusually sharp, concise screw-threading which appears to have been formed by using James Pennycuick's August 11, 1885 patent. These corresponding features suggest the possibility that the C.E.L. Co. and Pettingell Andrews ones were manufactured by someone who had rights to access to Pennycuick's threading technique. 
Pettingell-Andrews Company insulators are considered rare in the Boston area, where the majority of them have been located. Most of the in-service reports were on fire alarm signal lines.
These specimens generally are of medium aqua glass. Some have been located in much lighter aqua shades, while others are known in deep bluish aqua. All appear to have been produced between the late 1880's and 1900.