Recently purchased a skytone line drop off insulator I've been looking for and thought it would be neat to see all the ones I have together in a group. The top one was made by Porcelain Products Inc. under patent number US2,517,221 in 1950. It is marked with just a simple recessed embossed 8-1-50. It served as a secondary spool and as dead end tie offs. My example also has the metal reinforcement band bolted on. The bottom three were cataloged by Line Material Co. as multi dead end tie off insulators. The three I have were all associated with L.M. Co. The first one is ink marked with the L M logo, The second is ink marked ME 80 5 (McGraw Edison Co. 1980, 5 is probably for shift or part of the year quarter. Last is marked with the Illinois outline with an I in the middle (Illinois Electric Porcelain Co.). I haven't found a patent for these yet but they sure are neat. Wonder if they ever made any of these in other colors. I seen a picture of the P.P.Inc. one in white and are searching for that also.