Abstract: An adjustable socket for engaging various sized fastener projections such as hexagonal nuts, includes a socket body with a cavity having a spring-biased plate pushing nested and concentrically positioned sliding sleeves toward the socket opening and their first position. A retainer member restrains the outer sleeve and offset lower sleeve ends form interlocking shoulders to restrain the inner sleeves. Magnetic strip pairs are between the sleeves and integrated therewith to form magnetic couples when the sleeves are in the first position. The intrusion of a nut will encounter one or more of the smaller sleeves and shear the magnetic coupling between the largest of the smaller sleeves and the next largest sleeve. Magnetic couplings between the larger sleeves are maintained during the downward displacement of the smaller sleeves thus keeping such sleeves in the first position. The sleeve bore shapes can be chosen to engage all shapes of fastener projections.