Neptune Systems' SKY Diffuser Kit enables quick and hassle-free tweaking of the shimmer emitted from the SKY light, no programming or changes to light settings required. Out of the box, the SKY emits shimmer through four unblocked LED openings. Most aquarists appreciate this balance, but Neptune Systems also cater for those who want more control. Simply pop the Diffused Shimz inserts into the four white LED sections of the diffuser panel to alter the shimmer output. The results are instantaneous. This kit includes 4x Diffused Shimz Inserts.