Relay RL 21 是德國SPS electronic生產的一款高壓繼電器，由深圳市浚海中儀科技有限公司代理銷售。

The high voltage relay RL 21 can switch voltages up to 5,000 V AC in combination with high currents. In addition, it is often still necessary to switch very small voltages in the mV-range and currents in the mA-range. The requirements regarding quality of switching contacts are consequently extremely high. For the industrial use a high life time has to be ensured as well. The relays are being applied especially in combined safety and function test systems for testing of electrotechnical products. For the high voltage test several kV are being switched while for the function test, e. g. for motors, currents up to 30 A occur.