A device, for applying a flowable medium to a surface, includes a container, equipment to be worn on a back, a hose and a hose adapter, which can attach the hose to an outlet opening of the container, and which includes a ventilating element. The device further includes a handle having an end to which a wiping or applying device is mounted. The equipment includes a mounting plate attached to supporting straps to hold the container; and the container includes coupling elements for coupling the container to the mounting plate. A duct of the device extends from a first end of the hose, such that, when the hose is attached to the container, at the first end thereof, by the hose adapter, the duct conducts the flowable medium, from the container, to an outlet of the handle, which outlet is spaced apart from the wiping or applying device.