Radio Frequency Radio frequency (RF) is the latest beauty technology. RF skin-tightening treatment is an effective way to rejuvenate skin, reduce wrinkles and enhance skin elasticity. The RF heats the dermis, the deepest skin layer, without damaging the epidermis, the top layer of skin. It stimulates the structural change of the collagen fibers and elastic fibers to its original elasticity, reducing lines and wrinkles. An immediate skin-tightening effect will then be achieved without risk. Also, radio frequency can promote tissue metabolism, repel cellulite, tighten the skin, strengthen the skin's elasticity, and so on. Its effect will last for a long time. Meanwhile, it can enhance muscle elasticity and improve cell metabolism. It creates effect like internal explosion, meaning that the expansion and compression of waves produce a lot of tiny spaces inside the liquid. The gas and vapours exist in these tiny spaces. In the compression cycle, supersonic waves impose a positive pressure on the liquid molecule, whereas a negative pressure is created through the expansion cycle. There is a cohesion effect inside the liquid or biological tissues. Inside the low-density lipocyte, the cohesive effects are comparatively weak. A negative pressure, which is relative low, can create tissue gaps easily. It is called cavitations in physics. The effects of the explosion inside and outside the cells will increase the molecular movements so as to achieve a high energy state, which then leads to the lipocyte cracking.