The Faithfull FAIPITCHMA Screw Pitch Gauge is a handy gauge which quickly determines the pitch of various screw threads.The high-quality polished tool steel leaves are clearly marked with size and a locking device at both ends to securely lock the leaves. Specifications: Number of Leaves: 55.US National 60 Degree Threads: 4-42 tpi.Metric 60 Degree Threads: 0.25-6.0mm.   Ref: UTTK9673