Hyperbolic Match Output
Maker: PICKETT & ECKEL (USA)
Model: N4-T Vector - Type LOG LOG Dual - Base Speed Rule
Scales Front:||Three cube root scales 3√ , DF || CF, CIF, T&T, ST, S&S, CI, C || D, DI, Two sqrt scales √ ||
Scales Back: || LL1&LL1, LL2&LL2, DF/M || CF/M, Th, Sh&Sh, Ln, L, CI, C || D, LL3&LL3, LL4&LL4 ||
Gauge Marks: Gauge Marks on scales: π , π/4 , and R are on C, D, CF, DF, CF/M, DF/M, CI, DI, and CIF; e is on C, D and LL3; and marks 1° ' and " are on ST.
Construction: 25 cm.; White film over Aluminum, Cursor is not framed, Adjustable metal brackets.
Source: Herman's Archive
Information: Same rule but different colors as Model N4-ES Vector - Type LOG LOG Dual - Base Speed Rule which has a yellow plastic film over Aluminum. There is a version with Gold (Brass) end braces and Gold screws on Cursor.