What is radiofrequency?
Technically speaking, radiofrequency is the number of oscillations (or waves) per second of the electric and magnetic fields within the radio waves portion of the electromagnetic spectrum.It is lowest of the electromagnetic radiation frequencies within the spectrum, which itself spans from radio waves, microwaves, infrared, optical (visible light), ultraviolet, x-rays, to gamma rays.By feeding an alternating current (AC) or voltage through an antenna or electrode, electromagnetic waves can be generated that radiate through space at the speed of light; called radio waves. Radiofrequencies, or radio waves, have wavelengths ranging from less than a centimetre to as long as 100 kilometres.
UK domestic electricity which itself is an alternating current could in theory be used for "electrosurgery", however as most people know, contact with this kind of electric current can cause very undesirable effects such as electrocution and uncontrolled neuromuscular (nerve and muscle) stimulation. However, if the frequency of the alternating current is raised above the response time of neuromuscular structures, we find the radiofrequency range which can safely be used for medical/surgical applications.
By applying RF energy to the human body, which can conduct current and therefore act as part of the electrical circuit, any resistance encountered by the energy flow will cause heat to be produced at the site of maximum resistance, which can be used to cut or coagulate tissue.
When comparing non-ablative (procedures that do not involve the destruction of the outer layer of the skin) techniques, RF energy differs from laser (light) energy in that light energy tends to scatter or absorb into the upper layers of the skin, making it difficult to deliver sufficient heat into the deeper layers without damaging the skin's surface. 
Lasers therefore affect collagen in the upper dermis, improving fine lines, wrinkles and skin texture, while RF energy is able to penetrate deeper into the skin and affect the deeper dermis and subcutaneous layers, causing tightening and improvements to the underlying tissue structure, but with little change in skin texture or fine lines and wrinkling.
Function and therapeutic theory 

1) Adiposity:
Deep diathermy;
Blood vessel dilatation;
Enhance oxygen fluid, advance oxygen-taking exercise, upgrade blood and lymph circulation, exhaust toxin and
waste, activate metabolism;
Dispel and soften celluliate tissue;
Attain effect of weight reduction and controlling fatness.
Main effency:
Improve astriction.
Burn fatness.
Enhance flexibility.
Reduce pain.
Firm slack skins after producing baby.
2)Rejuvenate skin.
Deep diathermy;
Blood vessel dilatation, enhance blood fluid
Supply oxygen and organic nutrition transportation, strengthen cells function, advacne blood and lymph circulation.
Activate metabolism function, make collagen albumen producing.
Tender, lift and firm skin.
Main effency:
Lift and firm skin, dispel wrinkle, eye bag.
Whiten and tender skin.
Control ance, shrinken pores.
Make up water, sculpture face shape.
3) Treat pain.
Deep diathermy;
Activate cells metabolism function,
Relax muscle
Increase fibre albumen tissue dilation, letdown anchylosis.
Ease pain.
Main effency:
Ease muscle pain.
Letdown anchylosis.
Relax fatigue of all body.

Feature of portable RF/mini equipment

1-Painless to skin without taking anesthetic pills or surgery.

2-Safe and effective

3-Taking little time for recovery and no effect on regular working or living

4-Minimum side-effects

5-Obvious & lasting long-time results