The Diffused Shimz by Neptune Systems is designed to reduce shimmer from the SKY LED Light.
The Neptune SKY LED was designed with a hybrid diffuser to suit the tastes of most aquarists. The hybrid includes several openings where white LEDs can shine through with no diffusion, bringing back some of the shimmer usually lost with traditional diffusers. These openings are referred to as "Shimz". The SKY comes equipped with Clear Shimz as its default; However, those who wish to reduce shimmer even further can purchase these Diffused Shimz, which can be easily swapped in to replace the Clear Shimz installed on your SKY Light.