Kremona Mandolin Pickup, 1/4 Carpenter Jack w/ Volume Control MP-2. Low-profile portable bridge-mounted piezo with volume control for mandolin. MP-2 is a portable piezo pickup for mandolin, engineered and handcrafted by KNA. The innovative design allows an entirely external setup without any modifications to the instrument. The complete installation can be completed within a matter of minutes. The amplified tone is balanced and natural, providing full frequencies from bass to treble registers of the mandolin.