A prosthetic device comprising: a pylon; a connecting portion for connecting to a person using vacuum; a housing attached to and encompassing a section of the pylon; and a control structure for controlling an amount of vacuum used to connect the connecting portion to the person, wherein the control structure is housed within the housing, wherein the control structure includes: a vacuum pump in fluid communication with the connecting portion for controlling an amount of vacuum used to connect the connecting portion to the person, a vacuum sensing mechanism configured to provide signals indicating the amount of vacuum in the connecting portion, a movement sensing mechanism configured to provide signals indicating at least one of acceleration of the prosthetic device, orientation of the prosthetic device, force experienced by the prosthetic device, and a direction of force experienced by the prosthetic device, and a controller configured to: receive signals from the vacuum sensing mechanism and the movement sensing mechanism, control the vacuum pump, store a threshold vacuum level, calculate a calculated vacuum level based on the signals from the vacuum sensing mechanism, and control the vacuum pump based on at least a comparison of the calculated vacuum level to the threshold vacuum level characterised in that the housing includes a removable section configured to be removable from a remainder of the housing, wherein the removable section holds a battery or a battery and a wireless transceiver. a pylon; a connecting portion for connecting to a person using vacuum; a housing attached to and encompassing a section of the pylon; and a control structure for controlling an amount of vacuum used to connect the connecting portion to the person, wherein the control structure is housed within the housing, wherein the control structure includes: a vacuum pump in fluid communication with the connecting portion for controlling an amount of vacuum used to connect the connecting portion to the person, a vacuum sensing mechanism configured to provide signals indicating the amount of vacuum in the connecting portion, a movement sensing mechanism configured to provide signals indicating at least one of acceleration of the prosthetic device, orientation of the prosthetic device, force experienced by the prosthetic device, and a direction of force experienced by the prosthetic device, and a controller configured to: receive signals from the vacuum sensing mechanism and the movement sensing mechanism, control the vacuum pump, store a threshold vacuum level, calculate a calculated vacuum level based on the signals from the vacuum sensing mechanism, and control the vacuum pump based on at least a comparison of the calculated vacuum level to the threshold vacuum level characterised in that the housing includes a removable section configured to be removable from a remainder of the housing, wherein the removable section holds a battery or a battery and a wireless transceiver. a vacuum pump in fluid communication with the connecting portion for controlling an amount of vacuum used to connect the connecting portion to the person, a vacuum sensing mechanism configured to provide signals indicating the amount of vacuum in the connecting portion, a movement sensing mechanism configured to provide signals indicating at least one of acceleration of the prosthetic device, orientation of the prosthetic device, force experienced by the prosthetic device, and a direction of force experienced by the prosthetic device, and a controller configured to: receive signals from the vacuum sensing mechanism and the movement sensing mechanism, control the vacuum pump, store a threshold vacuum level, calculate a calculated vacuum level based on the signals from the vacuum sensing mechanism, and control the vacuum pump based on at least a comparison of the calculated vacuum level to the threshold vacuum level receive signals from the vacuum sensing mechanism and the movement sensing mechanism, control the vacuum pump, store a threshold vacuum level, calculate a calculated vacuum level based on the signals from the vacuum sensing mechanism, and control the vacuum pump based on at least a comparison of the calculated vacuum level to the threshold vacuum level characterised in that the housing includes a removable section configured to be removable from a remainder of the housing, wherein the removable section holds a battery or a battery and a wireless transceiver.