 Snap gauges may be machined and ground out of a single block of metal or adjustable snap gauges, which have movable anvils that may be adjusted over a limited range of sizes, may be used.They may also be of built up construction in which one or more gauge blocks or feeler gauges are sandwiched between two anvils.Adjustable snap gauges may be reset to compensate for wear or re-tasked for measuring a different dimension and can be purchased off the shelf and set rather than needing to be fabricated from scratch when a new gauge is needed.