The key feature of our skin permeation technology is our patented feedback control algorithm to achieve optimal and pain-free skin preparation for our transdermal sensing technologies. While the system is in operation, the Prelude SkinPrep System measures the real-time electrical conductivity of the test skin site. The system turns off automatically when the conductivity measurement reaches the appropriate level as identified by the algorithm, thus producing individualized, optimal skin permeation. As a result, the system only removes the outmost layer of the epidermis, the stratum corneum, a layer of about 0.01 mm in thickness consisting of only dry, dead skin cells. With the advantages of our proprietary feedback control algorithm, we believe the skin permeation process is safe, effective, fast-acting and painless.