Selenium RPST200 Replacement Diaphragm Selenium RPST200 8 ohm replacement diaphragm for Selenium ST200 super tweeter. Selenium RPST200 Replacement Diaphragm Selenium RPST200 8 ohm replacement diaphragm for Selenium ST200 super tweeter. Selenium RPST200 8 ohm replacement diaphragm for Selenium ST200 super tweeter.