F.I.L. is the mark (on cap and on porcelain) of this small (110 mm. diameter) clevis type suspension. FIL manufactured insulators in the period 1917 - 1937, and means Fabbrica Isolatori Livorno (Factory of Insulators Leghorn). The characteristic light brown color that distinguishes these insulators is called "LIVORNO" by italian collectors.. On cap there's the inscription M 253 (Catalog number). Here still wet after a good bath of HCL and then, water