Today, on the occasion of the 50th anniversary of the ISO 3159 standard, and true to its unifying mission in the service of Swiss watchmaking, the COSC is introducing a new certification. Designed to address today’s technical realities and the evolving expectations of both manufactures and clients, it builds on the existing standard.

Conceived as a complementary extension rather than a replacement of the current certification, this new distinction strengthens performance requirements through:

• Thest conducted on the finished watch

• a reduced rate tolerance of 6 seconds per day (-2+4 s/ day)

• Magnetic resistance tested at 200 Gauss

• Verification of the stated power reserve

Watches that meet all of these criteria will be awarded the title:

Excellence Chronometer Certified

This new certification supports manufactures in addressing today’s challenges and illustrates the COSC’s ongoing commitment to uniting Swiss watchmaking around excellence and innovation, without ever compromising the independence and rigor of its testing.