In order for these LEDs have not the optimal range of about 495-500nm, but to use already much better.
The violet LEDs with 420nm wavelength around are also of good quality and have, unlike many cheap fake Leds, silicone lenses! This is important because plastic lenses after a short time by the additional available UV radiation are brown and hardly provide a service after a short time.
The LEDs are soldered to clean the aluminum plates and is certainly to 3W LEDs (no fake LEDs). This is easily detected on the emitter size.
The LEDs can be very good from the aluminum plate solve them without using them. One only needs a strong soldering gun (from 100W) or a hotplate. In addition, the LED panel (Aluseite) is simply placed and heated to the heating wire of soldering gun or stove. Once the solder joints of the LED start bubbles form (or shortly thereafter), the LED itself can be lifted with tweezers. It's better here, the Led to heat quickly and as soon as possible to withdraw. A heating for too long damages otherwise the LED and shorten the shelf life. The UV LEDs the silicone lens should not be touched unnecessarily because this is very sensitive and the LED can be easily damaged.
Furthermore, the LEDs are packed neatly and were quickly (3 days) from UK delivered.
For the price absolutely recommended, especially since there are real quality 3W emitter.
I assume that the other colors of the same good quality.