1. This is one of the variants of the Model 4 by Pickett. I have noticed that there are a number different scales and layout in other versions of this rule on the web. This also applies to other early Pickett rules as if they were playing around with the design on a regular basis. This is understandable as the Pickett rules were not 'engine divided' but printed on a standard rule base so making new versions of a rule after feedback from customers was probably easier and therefore a more normal practice for Pickett in the early years.
2. Refer to Model 4 (1) for another version of this rule with a slightly different layout and scale changes.

Brand	Pickett
Model	Model 4 Vector Hyperbolic Log Log
Country of Manufacture	USA
Scales Front	3√1, 3√2, 3√3, DF [CF, T, ST, S, CI, C] D, DI, √1, √2
Scales Back	1/N1, 1/N2, 1/N3, 1/N4, DF [CF, Th, Sh1, Sh2, CI, C] D, N1, N2, N3, N4
Number of Scales	30
Slide Rule Materials	Magnesium
Cursor Materials	Metal/Plastic
Cursor Lines	1 Front, 1 Rear
Scale Length	25 cm
Length	30.7 cm
Width	5.2 cm
Condition	Good
Documentation	None
Accessories	Rubber case