Laguna’s Winterizing Kit includes all the necessary products you will need for protecting and keeping goldfish and koi alive during the winter months. The Kit Includes: - Laguna PowerHeat 500-watt De-Icer (PT1643) - Laguna Aeration Kit (PT954) - Laguna Pond Netting 4.6 x 6.1 m (15 x 20") (PT1630) - Care Guide The Pond Netting keeps leaves and debris out of the pond, reducing the possibility of submerged circulating pumps becoming clogged. The De-Icer keeps and maintains a thawed, open area at the pond surface, allowing toxic gases from fish respiration and decomposing organic matter to escape. The De-Icer and Aeration Kit are energy efficient, easy to install, and suitable for garden zones 1 to 8 (-6 °C /20 °F).