Gerber TP007100B Variable Scale

Country of manufacture: USA,            Date of manufacture: ____,      Serial No.: 107363
Overall length: 30.4 cm,          Width: 3.5 cm,           Thickness: 1.3 cm           Weight: 122.6 gms.
Materials & Construction: Black aluminum rectangle, to which two aluminum strips, also black, are screwed. Three scales RI, I, and L10 are printed on the bottom strip. The aluminum blocks at either ends of the main assemby (rectangle and two strips) are unpainted, as are the L-shaped runner which moves to left and right along the groove between the two black strips. A rectangular piece of clear plastic with a vertical indicating line is screwed to the bottom of the runner, so that it sits directly over the scales. A triangular spring streches between the left end block and the top of the runner. Every fifth coil is painted green or red, in an alternating pattern. (Description taken and modified from the Harvard Collection of Historiical Scientific Instruments, here.
Scales: 3
RI Reciprocal scale w/values 100-10
I Linear scale w/values 1 - 10
L10 Logarithm base 10
Condition: C5 (Normal signs of use)
Came with: Brown leather covered case