Breg's 3B Putty and Wooden Plug Set can be used to stop crossover line breaks or fuel tank punctures. Breg's 3B Putty is a non-toxic, pre-mixed putty. In cases such as tank punctures, Wooden Plugs can be jammed into the hole to minimize fluid release before 3B Putty is applied. When pressed into a puncture it forms an immediate seal to control leaks and spills. No preparation needed. Sticks to greasy, rusty or dirty surfaces. No mixing necessary.