First, I ran the relay together with the old 21W flasher bulbs. The Blink-clock had slowed down over the old relay. Then I have the light bulbs to LED lamps (Warm White BA15S / 27x SMD 5050 / approx 3W) exchanged. The flashing rate corresponds again exactly the old clock, the LED indicator lamps are a little lighter than the old bulbs. I am very pleased!