When it comes to massage chairs, there are three different types of rollers: 2D, 3D, and 4D. The earliest and most fundamental are 2D, and the most recent and sophisticated are 4D. Does this mean you should exclude 2D and 3D chairs altogether and only consider those with 4D rollers? No. There is little doubt that 4D technology outpaces 2D and 3D, but it's difficult to say for certain how the experience will be since comfort is subjective. Due to its simplicity, 2D rollers (and, to a certain extent, 3D rollers) can be simply integrated into a massage chair without the need for a lot of software. Because manufacturers are familiar with this kind of technology, they are able to design and build genuinely amazing products.While there are many great chairs, we're still in the "early days" of 4D rollers, so there is a lot way to go.3D rollers move up and down along the vertical, side to side along the horizontal, and extend in and out for more deep tissue.When referring to the Allure particularly, it includes 3D rollers and an SL-Track. The SL-Track, often referred to as the L-Track, is one in which the track reaches all the way down from the neck to the glutes. The majority of people mistakenly believe that SL and L-Track are two distinct concepts due to nomenclature. They are interchangeable!