These are for 1.375in x 24tpi tubes that are available from other brands.
. The Silco mounts protrudes .60 from the shroud or pig tube and are tightened by a 1 1/4″ wrench or adjustable wrench. Silco are meant to fit brakes with the outside threads 1 1/8 x 12 (The joker, The cyclone, Angel and demon, some silcencerco brakes, and battlecomp) Made of Carbon steel. 1.375×24 for SDTA MBTA Protude .50 and are tightend by a 1″ wrench.