Hemingray made several specialized insulators over the years, including glass floor tube insulators (also known as wall tube insulators) and bushings. The purpose of these insulators was to carry a line through the floor or wall of a building, insulating it on all sides as it passes through. Floor tube insulators are not currently assigned CD numbers, though I would imagine they will be in the future as we learn more about them.

Based on catalogs dating from 1903-1918, we know that Hemingray offered floor tubes in at least 13 distinct styles, as listed in the table below. The style numbers range from No.120 to No.132. Like most of Hemingray's break knob spools, so far none of the floor tubes have been found embossed.

There are three distinguishing characteristics of a Hemingray floor tube insulator: the length, the bore (tapered hole diameter), and tube type (screw, without screw, or split plain). The diagram on the right shows how they are measured. Most of the floor tubes are of a screw type with a 6- or 8-sided head and outer threading; only No.124 and No.132 are not. The No.132 is also unique in that it is a two-piece insulator that is tongued and grooved.