A powered surgical tool including: a housing; a power generating unit disposed in the housing; an attachment that extends from the housing and that is connected to and actuated by the power generating unit for performing a surgical/medical task; a control module disposed in the housing, the control module having: a shell formed from at least one panel (51, 52, 53, 54 and 63); a circuit board (59, 142) disposed in the shell, wherein the circuit board includes components for regulating operation of the power generating unit; at least one conductive pin that extends through an opening in one of the panels for electrical communication between the circuit board and components external to the module; and a seal unit disposed in the panel opening that extends between the pin and an inner wall of the panel that defines the opening, characterized in that: the seal unit consists of: an outer stop disposed in the panel opening around said pin, said outer stop extending to the opening-defining inner wall of said panel; an inner stop disposed in the panel opening around said pin, said inner stop extending to the opening-defining inner wall of said panel, said inner stop being spaced away from the outer stop; and an active seal (79, 127) disposed in the panel opening around the pin and located between the outer and inner stops, said active seal including: a boot, said boot shaped to have: an inner skirt that extends circumferentially around the pin adjacent the opening-defining inner wall of said panel; an outer skirt disposed around said pin adjacent the inner wall of said panel; and a base that extends between said skirts; and at least one biasing member that is located between said skirts that biases the outer skirt against the panel inner wall or the inner skirt against the pin. a housing; a power generating unit disposed in the housing; an attachment that extends from the housing and that is connected to and actuated by the power generating unit for performing a surgical/medical task; a control module disposed in the housing, the control module having: a shell formed from at least one panel (51, 52, 53, 54 and 63); a circuit board (59, 142) disposed in the shell, wherein the circuit board includes components for regulating operation of the power generating unit; at least one conductive pin that extends through an opening in one of the panels for electrical communication between the circuit board and components external to the module; and a seal unit disposed in the panel opening that extends between the pin and an inner wall of the panel that defines the opening, characterized in that: the seal unit consists of: an outer stop disposed in the panel opening around said pin, said outer stop extending to the opening-defining inner wall of said panel; an inner stop disposed in the panel opening around said pin, said inner stop extending to the opening-defining inner wall of said panel, said inner stop being spaced away from the outer stop; and an active seal (79, 127) disposed in the panel opening around the pin and located between the outer and inner stops, said active seal including: a boot, said boot shaped to have: an inner skirt that extends circumferentially around the pin adjacent the opening-defining inner wall of said panel; an outer skirt disposed around said pin adjacent the inner wall of said panel; and a base that extends between said skirts; and at least one biasing member that is located between said skirts that biases the outer skirt against the panel inner wall or the inner skirt against the pin. the seal unit consists of: an outer stop disposed in the panel opening around said pin, said outer stop extending to the opening-defining inner wall of said panel; an inner stop disposed in the panel opening around said pin, said inner stop extending to the opening-defining inner wall of said panel, said inner stop being spaced away from the outer stop; and an active seal (79, 127) disposed in the panel opening around the pin and located between the outer and inner stops, said active seal including: a boot, said boot shaped to have: an inner skirt that extends circumferentially around the pin adjacent the opening-defining inner wall of said panel; an outer skirt disposed around said pin adjacent the inner wall of said panel; and a base that extends between said skirts; and at least one biasing member that is located between said skirts that biases the outer skirt against the panel inner wall or the inner skirt against the pin. an outer stop disposed in the panel opening around said pin, said outer stop extending to the opening-defining inner wall of said panel; an inner stop disposed in the panel opening around said pin, said inner stop extending to the opening-defining inner wall of said panel, said inner stop being spaced away from the outer stop; and an active seal (79, 127) disposed in the panel opening around the pin and located between the outer and inner stops, said active seal including: a boot, said boot shaped to have: an inner skirt that extends circumferentially around the pin adjacent the opening-defining inner wall of said panel; an outer skirt disposed around said pin adjacent the inner wall of said panel; and a base that extends between said skirts; and at least one biasing member that is located between said skirts that biases the outer skirt against the panel inner wall or the inner skirt against the pin.