Birch structure with thickness of 10 mm. 10mm back cover, inner hole thickness 20mm. Birch front cover, varnished with translucent stains in different colours: natural, walnut, red, green, blue or black. 4 strings mounted in a "V" shape. Improved tuning system in 2016. Easy to use and precise tuning thanks to 2 knobs mounted on the base of the drawer.