A receptacle unit of a connector for sealably engaging and disengaging contacts therein can include one or more closed inner chambers. At least one of the one or more inner chambers being configured to contain a receptacle contact. Each receptacle contact can be configured to engage a plug contact of a plug unit of a connector. A closed cavity can be at least partially in contact with each inner chamber. The closed cavity can contain a deformable material. At least a portion of the closed cavity can be configured to be movable with respect to another portion of the closed cavity to permit balancing of pressure of the deformable material within the closed cavity to pressure outside of the closed cavity.