To quantitatively verify the performance of the CS, various experiments were conducted. These experiments were approved by the Institutional Review Board of Korea University, Seoul, Republic of Korea (IRB no. 1040548-KU-IRB-18-101-A-2). The experiments addressed electrochemical stability, verification on various skins (including people from Asian and Western countries), long-term stability, stability concerning severe detachment artifacts, simultaneous monitoring of multiple EP signals, stability in dynamic environments, and offline-online BCI application. A total of 60 individuals aged 20 to 40 years participated in the experiments (table S1). A numerical program (MATLAB, MathWorks, USA) was used to preprocess, separate, and classify datasets. For signal processing, BBCI-Toolbox (46), EEGLAB (53), and OpenBMI toolbox (47) were applied.