Current Culture 4-Site Multi-Mod Expansion Kit for Under Current Double Barrel with Four-Site Lids (4 x 5.5" Net Pots)Increase The Number of Growth Modules On Your Under Current Double Barrel or Under Current With This Expansion Kit From Current Culture! All Expansion Kits Now Include: Multi Mod Growth Module, Aeration Manifold Fittings, and Air Hose Whips. NOTE: This multi mod expansion kit is designed to be used to expand the new 2019 multi mod under current systems. This expansion kit will NOT work with the classic systems. If you are looking to expand an old