This string range represents one of the major innovations brought by Aquila Corde Armoniche. This new formula combining metal and synthetic elastomers exponentially amplifies the instrument's volume and gives it an exceptional sound balance. The improved feel and higher tension facilitate modern techniques such as slap, slide, and artificial harmonics. The deep and powerful effect of the double bass is easily imitated, and this significant volume allows the instrument to be used acoustically, even within a band. Compared to traditional elastomer strings for bass ukuleles, Thunderbrown strings offer several advantages: They are made from plant-based bioelastomers. The addition of metal to the plastic blend, in the form of micronized copper, is minimal on the first string and maximal on the fourth, ensuring perfect acoustic homogeneity in play. These strings guarantee a perfect slide of the left-hand fingers. The diameter is small enough to be comparable to that of standard wound strings for acoustic basses. The sound is so powerful that they can be installed on instruments with a traditional soundboard (i.e., without a solid top) and played without amplification. The string tension has been increased compared to our Thundergut, Thunderblack, and Thundered strings.