http://fearsteve.com/education/glass-insulator-1/ William Franzen & Sons- W F & S MIL marking on base of amber beer bottle. All insulators, glass and porcelain, in my opinion, have some worth. The value may relate only to the truth that a piece is an authentic relic of bygone days, or an object that can serve as a conversation piece or item of property decor. Although this could be observed as a unfavorable, this destroyed failure-mode co Tue, 16 Apr 2024 11:29:04 UTC en