Simple and easy to use, these 5 channel mixer pre-amplifiers are suitable for adding microphones to any sound system. The ST4 & ST4E both come built with XLR-¼ combo connector inputs. The ST4E comes with high-fidelity isolation transformers and +15V phantom power.","Plus, with over a half-century of experience in the industry, Grommes~Precision backs the ST4E with its unbeatable expertise and Precision Assurance Pledge: a 5 year warranty and a 30 day money back guarantee.