UNIVERSAL GENEVE, STEEL, BUMPER MOVEMENT, RETAILED BY CAMERER CUSS, REF. 20005 1

Featuring an interesting bumper rotor named after the slight “thud” perceived when the rotor hits a spring and bumps back. Unlike modern rotors that perform a full 360-degree spin, the bumper version moves back and forth at around 120 degrees, ‘bumping off’ a pair of springs on the opposite sides of the bridge. This effective way of accumulating kinetic energy was invented by the English watchmaker John Harwood in 1923