Notes: "The K&E 4088 slide rule was a combination of the scales from the Cox Duplex, and the S, L, T, and K scales from the single-sided “Polyphase” (4053) slide rule. It was introduced in 1913 and made until 1939. The 4088 did not originally have a B scale, that was added in 1922. The presence of the B scale and the frameless glass cursor indicate that this one was made between 1922 and 1936. "
