These are pretty interesting insulators since there is a distinct size and shape variation among them as you can see. The two on the left look especially "perculiar". I never noticed that much of a difference among the composition insulators remaining in use along street trolley routes in Boston. In other words they appear to be the same. Examples I have noticed were dark brown bakelite (or something close to this material) with one-inch pin threads and small J.M. Anderson Co. Boston lettering around the area near the pinhole. The latter was an electrical supply company in Boston for many years.

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