Seated deep inside our quick coupler fittings is an o-ring that creates a tight seal between the quick connect coupler and quick connect plug, to eliminate the possibility of leaking water. With use, this oring can become damaged and require replacement. We offer Buna o-rings for pressure washing temperatures up to 210 Degrees F, or Viton o-rings for temperatures up to 300 Degrees F. Our Viton orings can also withstand aggressive chemicals, such as caustic pressure washing detergents and acids.