A professional who examines and adjusts hairspring assemblies to ensure horizontal and circular alignment of hairspring, using truing ii calipers, loupe, and watchmaker's tools. Responsibilities include:

• Mounts hairspring and balance wheel assembly between jaws of truing calipers.
• Turns wheel of calliper and examines spring to determine if centre coils appear as perfect circles, using loupe.
• Bends inner coil of spring away from or toward collet to locate centre of collet in centre of spring and to correct errors resulting from faulty colleting of coil, using tweezers.
• Estimates space between collet and first inner coil to determine if space is within acceptable limits, and bends coil to correct errors, using tweezers.
• Examines plane of hairspring to determine if coils are parallel to plane of collet and raises or lowers individual coils to correct discrepancies, using tweezers.