Apparatus (10), including an enclosure, a fluid-tight bag (12) located within the enclosure, and a fluid-tight valve (16) connected to the fluid-tight bag. The apparatus also has a tube (34), having a first end connected to the fluid-tight bag via the fluid-tight valve, and a second end connected to a balloon (24) within a breast implant fitted to an implantee. The apparatus further includes a spindle (56), located within the enclosure, connected to the fluid-tight bag, and configured to rotate under control of the implantee so as to roll the fluid-tight bag onto the spindle or to unroll the fluid-tight bag from the spindle, and thus transfer a fluid, contained in the balloon, the tube, and the fluid-tight bag, therebetween.
