Notes: "The K&E 4065T is an 8-inch duplex slide rule, and added S, T, and L scales to the model 4065, which was made concurrently. The 4065 was an 8-inch version of the 10-inch 4071, which was the 1909+ continuation of the original Cox Duplex slide rule. The 8-inch models 4065 and 4065T were introduced in 1909, the 4065 model number having previously been used for a 5-inch slide rule. The date for this slide rule is 1910 to 1913, with the L-shaped end braces and the clamshell cursor putting the lower and upper limits on that range respectively. "
