Picked up these neat Neon Sign insulators over the weekend. Two I found at the Gettysburg N.I.A. show and the other online auction. From L-R- marked Standard Heat Resisting Housing/Cat No 100/Made In U.S.A./Pat Pend/ #D7967 & # D7732. Back is marked UL in circle 14. It is in ice blue tint. 2nd is a long 4 1/2" single groove, No Name, white porcelain. Never seen a porcelain one this tall before. Last is a No Name double groove white porcelain. This has a ribbed grip in the top groove and four teat rests on the bottom. It is kinda thicker than the others I have so must have been for heavy duty use. Hope you enjoy the pictures. Take care stay safe and be well to all.