A mechanical adjustable device described herein is adapted to enable changing the spatial shape of the device from a first shape to a second shape, while retaining the device in its second shape. Preferably, the device includes: a) a spring; b) a plurality of longitudinally extended ribs or wires that are capable of being bent, wherein these plurality of ribs or wires are circumferentially disposed along an enclosure confined by the spring, adjacent to the inner side of the spring; and c) a flexible sleeve or tube disposed longitudinally along the enclosure confined by the spring.