A 2 gallon water container that looks good, can water your plants for 1-3 weeks, and also prevents algae from growing. The bulkhead fitting and valve attach to 8mm supply line (IG15978, sold separately) that circulates around your plants. Any place you need watering, just cut the line with scissors, push the two ends of the tee attached to either the regular or XL Classic (order separately), and push the Classic into your potting mix. You can change the amount of water supplied by raising or lowering the jar. The handy wooden chalkboard makes it easy to record dates if you'd like to keep track of how long the water lasts.