Lisle 68150 Go-No-Go Feeler Gauge 22 steel blades Blades from 0.004 inches to 0.027 inches (0.102 - 0.686mm) are approximately 1/2 inches wide by 3-1/4 inches long Low gauge blades size are from 0.004 to 0.025 inches High gauge blades size are from 0.006 to 0.027 inches