Some folks need to up their game a bit. These devices have been recently approved by the FDA and they are definitely available in the U.S. although not widely so. I am not sure if the FDA approval is specifically for skin tightening, but there are many devices which have FDA approval for a somewhat different use, but physicians may use the device in any way that they feel the device would be effective. This is referred to as "off label" use.
The devices work by directing Radiofrequency energy in a very targeted way to the deep dermis. This allows for specific heating of the deep dermis while at the same time minimizing heating of the surrounding tissues and protecting the skin surface in particular from getting too hot.There is real time temperature monitoring built into the tip of the probe to protect the tissue from overheating. Heating the deep dermis to a specific temperature range will produce collagen contraction as well as stimulating the fibroblasts within the dermis to generate more collagen. These effects result in noticeable shrinking and tightening of the skin. Recent quality studies have been published which confirm the skin tightening benefits of these devices with impressive before and after photos. The specific way in which these devices work is unique to this technology and while results will vary from patient to patient it appears that the outcomes significantly exceed those of other devices currently on the market. Patient satisfaction rates are high and the devices are most definitely not just a marketing gimmick. It is unfortunate that some physicians will condemn a new technology with little knowledge or understanding of how the devices work and the potential benefits.
As with any new technology one needs to dig a little deeper into the actual research on how the device works and how safe it is, and one should not rely solely on the flashy marketing which will inevitably accompany the introduction of a new device into the aesthetic market. I have attached a reference for one of the peer reviewed papers on this technology.