Rule one is a helpful aid to 4mm scale modellers, by TS Design.

Features:

1:1 scale rule (mm)

1:87 scale rule (feet)

Centre finder up to 32mm off-centre

Wire/Rod diameter quick-checker (1/8”, 3mm, 2mm, 1.5mm, 1mm, 0.7mm, 0.45mm)

HO gauge back-to-back checker

HO track gauge checker

Minimum double track spacer

Average person height (1:87 scale)

NEM socket (top internal) height

Platform height

Average buffer centre height

Standard buffer spacing width

All in one pocket-sized package!