3M™ cavity wax Plus 38854 is a non-hardening, self-healing corrosion protection coating for internal auto body panels and structural enclosures, as well as new replacement parts. It is designed to cover and seal internal joints, hem flanges and other areas where OEM e-coat may be compromised. It will not chip, peel or crack. Use the 3M™ cavity wax plus wand kit for 360 deg coverage.