A device for attaching a tablet computer to the rear-side of a motor vehicle seat has a support for receiving the tablet computer. The belt tensioner of the invention is of the type with a base. As a result, a product to offer can be determined in a manner which maximizes casino profit. Caps screw threadingly engage the housing to clamp the pipe lengths in the housing. And an actuator is configured to selectively drive the dual clutch into one of its first and second clutching modes.