This document is a Product Similarity Declaration from Guangdong ERSE Acoustics Inc. It states that the bookshelf speaker models BS416, BS415, BS413, BS410, BS407, and NSY-BS401 are electrically identical. This includes the same hardware design, such as circuit design, PCB layout, RF module/circuit, antenna type and location, and components on the PCB. The models also share the same mechanical structure.
The only difference between the models is the Model Number and the appearance, specifically that the appearance does not contain metallic paint. The declaration is signed by Duan Deguang, a QC engineer at ERSE Acoustics, and dated April 21, 2025. The document also includes pictures of each model to illustrate the minor cosmetic differences.