A new conductor shape which we call a "Yin-Yang" coil is described. This coil produces a quadrupole magnetic well field, similar to the field of a Baseball-Seam coil, but with several important advantages. The Yin-Yang coil can produce a field of high mirror ratio (6, for example) with much less power than an equivalent Baseball-Seam coil. The Yin-Yang coil employs simple conductor shapes and has the flexibility inherent in two separate conductors. This permits the mirror ratio to be varied by changing the distance between the two conductors and to trap a plasma by energizing the coil segments sequentially.