The Under Current® Pro Expansion Kits are great for replacing a growth module in a situation where one of the original modules has been damaged or broken in any way. These kits come with all you need to get your Under Current® Pro back in working order. Under Current® Pro Expansion Kit Includes: one 35 gallon heavy duty ABS growth module with one Pro heavy duty ABS lids(s) with dual portholes, 3 in connecting joints with UC Spin-Tight Bulkhead, one 8 in net pot per growth module, one Aqua-Pore XL Air Diffuser per module and in-line filter(s). Choose from 1 site, 2 site, 3 site or 4 site replacements. These items are drop ship only.