As discussed in Chapter 59, the first commercially launched true nonablative fractional resurfacing (TNFSR) device was the 1,550-nm erbium-doped Fraxel laser (Reliant Technologies). It is the most widely studied device for this indication with the largest series of peer-reviewed publications and clinical experience. The Fraxel laser produces random patterns of microthermal zones (MTZs) with precise dosimetry to accomplish true nonablative fractional resurfacing. The first-generation Fraxel laser (Fraxel 750) employed two settings of microthermal zones (125 MTZ and 250 MTZ). The second-generation Fraxel laser (Fraxel Re:store) employs a variety of MTZ settings and is able to deliver fluences up to 70 mJ. Treatment levels (1–R3) reflect the density of MTZs, allowing for greater flexibility in delivery of energy. This is particularly critical in patients with darker skin types, for whom higher fluencies are required for indications such as acne scars, and variation of MTZs to lower levels allow for significant reduction in postinflammatory hyperpigmentation. Conversely, for indications that require more shallow penetration, such as melasma, both lower fluencies and lower treatment levels can be delivered. It is also possible to vary both treatment levels and fluencies on the same patient for different anatomic areas, allowing for very precise delivery of energy with the highest safety profile. Each Fraxel laser treatment delivers over a million MTZs. Ultrastructural analysis of Fraxel-induced wounds shows epidermal and dermal necrosis confined to the MTZs of submillimeter size.