In Stock. 45 Day Lowest Price - 100% Satisfaction Guarantee. The bass player's version of the popular personal effects device. The PX4B provides a total of 122 different high-quality effects including amp sounds. A total of 100 programs (50 presets and 50 user) cover a wide range of sounds suitable for all styles of music. 100 different rhythm patterns feature realistic PCM sounds and a wide range of styles!