This is our D-FLOW Random Flow Nozzle and comes in 3 standard sizes to fit all setups.
3/4 Nozzle rated up to 3500 LPH
1/2 Nozzle rated for up to 1600 LPH
Fluval Evo Owners: option of 1 1/2 inch nozzle or 2 1/4 inch nozzles, we recommend if you have an upgraded return pump to go with 1 1/2 inch nozzle to gain better performance.