Posi-Seal™ Head Seals To be used in conjuction with vertical storing leveler. The Posi-Seal™ is distinguished from any other seal of its type by its ability to maintain a complete perimeter seal while allowing the use of a full-function hydaulic leveler when installed with McHuire's Vertical Storing Hydraulic leveler(VSH).  A pocket behind the bottom seal pad accommodates the leveler lip in the below-dock position.