A film-supporting device is used with a waste-disposal unit. A central opening of the device in a transverse plane of the device has variable diametrical dimensions with a first diameter of greater dimension than the second diameter. The outline of the central opening has a shape optimized for receiving tubular film and for transportation costs, by having two of the first diameter of generally equal dimension and two of the second diameter of generally equal dimension, with the first diameter being the maximum diameter of the outline in the transverse plane, and with the second diameter being the minimum diameter of the outline in the transverse plane. The device has tubular film about an outward radial surface of the annular body. The free annular end is closed to form a bag. The opening of the bag is accessible through the central opening.
