These Helix Check Valve Assemblies come in the exact configurations to install many select pumps inside the Helix skimmer. Three types of discharge kits are available: Compact CVA for use with any compatible external pumps Regular CVA (3064 Models) for use with various submersible pumps Quick Disconnect CVA (3382 Models) with pitless adapter for use with various submersible pumps Not all submersible pumps will fit inside a Helix Skimmer with a discharge kit, but we have tested all the following pumps, with great results. SKU Compatible Pump Models *ShinMaywa Norus: 50CR2.15S, 50CR2.25S, 50CR2.4S, 50CR2.75S*Anjon Big Frog: 3000, 4200, 5500, 6300*Anjon Big Frog Eco-Drive: 3000, 4200, 5500, 6500Tsurumi: 2PU, 3PN, 4PN, 8PN 3382(QD) 507 Any external pump with 2" intake or smaller with adapter *We offer these pump models in a complete package that includes Helix Skimmer, Quick Disconnect CVA (3382) and pump.Note: When you buy your Helix Skimmer from Practical Garden Ponds, upon request we will pre-drill your skimmer so that any of the listed pumps and this discharge kit will easily fit. If you already have your skimmer but it is not pre-drilled, then upon request we can include a free cardboard template with purchase of a Helix Quick Release Discharge Kit so that you can drill the skimmer for easy installation of the listed pumps. NOTE: Use this link to purchase replacement O-Rings for the 2" Quick Release assembly.