A beverage container comprises a receptacle which has a central axis and is sealed by a lid of resilient material. The granules comprise at least one pigment selected from the group consisting of maganese oxide and iron oxide and a binder. The apparatus includes a moveable securing member. Then, a channel for data subcarriers between the pilot subcarriers is estimated by using a Wiener finite impulse response filter that has a separate coefficient according to the estimated delay spread value. The load status indicator utilizes a coil in series with the monitored device, a reed switch controlled by the coil, and field-effect transistors to control which light-emitting diode lights up depending on whether power is available and whether the monitored device is drawing current.