Sonor BT BasisTrolley, for mallets with resonator boxes (only in combination with BasisTrolley adaptors), for BasisTrolley table tops (without BasisTrolley adaptors), height and width adjustable trolley with 4 large, smooth running wheels, The Sonor Trolley System is very popular due to its versatile use and safe and easy transport of instruments with resonator boxes. A height and width adjustable BasisTrolley BT is the most important module within this system, colour black,