Avoiding scratches, dings, and related costs, plastic No-Mar gap gauges come in 4 series: short, go/no-go short, long, and go/no-go long. Go/no-go series are used to check gaps at location where only one gap with one tolerance spread is needed. Thickness sizes begin at 1/4 mm (0.01), 1/2 mm (0.02) and progress in 1/2 mm increments through 6 mm. Gauges can be arranged in any order and are used in auto and aviation assembly plants.