Dema (China) 1989 ~ 2023 34 "since the establishment of a complete PA system, design, quality, technology, service, our responsibility; It‘s beyond the definition of a sound box; It is a combination of sound, electronic control, mechanical parts application control and other components, each component of the GRF brand sound expansion system is a strict design, exquisite calculation and organic integration, so that it can play the best performance and extremely natural real sound and installation, storage, transportation and other excellent characteristics. GRF focuses on providing perfect technical information, learning and professional service support, so that every system can perfectly show the same excellent quality no matter when and where. Its business covers more than 60 countries and regions around the world. The products have been certified by CMA, ilac# MRA, CNAS, waterproof test report of outdoor products, environmental protection mark product certification, a number of computer software copyright, the enterprise has passed the credit evaluation certification, integrity management system certification, after-sales service certification, brand certification, supply chain management system certification. 1S09001:2015 Quality Management system certification, 1S014001:2015 Environmental management certification, 1S045001-2018 Occupational health and safety management, 3C certification, national high-tech enterprise EU CE certification, CB certification. EASE Acoustic Design software: SmaartLive Acoustic test and other software.