The S123 control key blank and the S145 control key blank are not interchangeable. Each ASSA control key is cut to a very specific profile that matches the control sleeve of its corresponding cylinder series. S123 → Designed for the Twin Exclusive / Twin 6000 series (851 profile). S145 → Belongs to a different ASSA profile family, with a distinct side‑milling and control sleeve geometry. Because the control key engages the retaining mechanism inside the cylinder (not the regular pin stack), even slight differences in profile mean it won’t operate another series.