The Water Pro Ozonator by Hydroquip. Available with 4 pin amp plug.

United Spas 03 Hot Tub Ozonator. 110V/220V with AMP cord

Spa Eclipse Next Generation Corona Discharge Ozone Generator by Del Ozone. Available with JJ Mini Plug ECS-1RPOZM-U or Amp plug ECS-1RPAM2-U. Del Ozone Eclipse Next Generation Replaces: ECS-1RPAM2-DV,ECS-1RPOZM-DV,ECS-1ROZM- 240/60, ECS-1ROZM, CDS-16