I'm no expert on Sejin Electron, but they're notable for being the most prominent customer of Futaba's clicky switches, using the standard negative mount (slot in the slider, cruciform peg in the slider, which is the opposite of Cherry MX). (The Cherry MX-compatible Futabas are typically found in some Chicony boards.)
They ping like crazy. I'd really love one of these keyboards, as the switches feel exceptionally smooth.
