Fluid Film is a lanolin-based, environmentally friendly oil that boasts several unique qualities, making it an excellent choice for rust prevention, particularly in frame undercoating applications. First and foremost, being an oil means that surfaces treated with Fluid Film are protected from rust. Additionally, its natural composition ensures that as it wears off, it does not contaminate water sources like other oils might. Another key feature is that lanolin has the remarkable ability to thin when agitated, which facilitates easy application inside and outside a vehicle's frame and floors. Once it settles and is no longer agitated, it thickens to a consistency similar to petroleum jelly, resulting in long-lasting protection that is resistant to being washed away by water and snow.