This through wall ball valve kit will enable you to fit a ball valve through either a kettle wall, or through an esky wall.  Kit includes:

• Italian ball valve
• 1/2" hose barb (for outlet)
• 2 stainless steel locking nuts
• 2 flat wider silicone O rings 
• 1 1/2 female hose barb
• threaded through wall nipple