The balance consisted of a circular steel balance wheel with two bimetallic strips attached diametrically. Each bimetallic strip terminated with a screw thread mounted with a weight or balance nut. The further along the strip this nut was screwed, the greater the compensating effect. Another part of the patent concerned an addition to the form of the balance spring—a coil of smaller radius at each end of the helical spring, which offered increasing resistance to the rotating balance as it turned towards the end of each vibration. This was an important invention, as it largely eliminated the problem of the positional adjustment of balance controlled watches. This device, known as the "Overcoil balance spring", is still used today in most precision mechanical watches.