Armin Strom is an independent watch manufacture based in Biel-Bienne Switzerland, and Kari Voutilainen is an independent located about an hour away by car in Môtiers.

The two Swiss watch brands have collaborated numerous times in the past and for their latest limited edition, two special Gravity Equal Force timepieces were produced exclusively for Cherry Creek, Colorado-based Oster Jewelers. I previously reviewed a Gravity Equal Force timepiece here, and master watchmaker Jordan Ficklin did a technical review of a Gravity Equal Force x Kari Voutilainen for Professional Watches here.

For this collab, Jeremy Oster of Oster Jewelers worked with Claude Greisler of Armin Strom and Kari Voutilainen to design the special color scheme and unique guilloche work pattern seen here. “We have developed the pattern together with Kari. The guilloche is hand-made in his workshop,” according to Greisler.

Not only do you get Voutilainen’s renowned guilloche work with these limited editions — but you also get an in-house-made Armin Strom movement and case, and significant hand finishing.

Speaking with Greisler about the production process, and in particular, how the edges of components such as the bridges are finished, he stated, “After the pre-bevelling, we use files to adjust the bevelling (corners and edges which cannot be made by a machine) and at the end, we hand polish.”

Introducing the Gravity Equal Force Kari Voutilainen Oster Editions. Presented in a 41 mm x 12.93 mm diameter case, you can choose either 18K reg gold with a blue guilloche work and gold hands or a stainless steel version with a brown-color guilloche and blued steel hands.

The Gravity Equal Force Kari Voutilainen Oster Edition 18K rose gold version retails for $36,800 and is limited to 10 pieces and the stainless steel version retails for $26,000 and is also limited to 10 pieces.