This set lets students practice the action of using an Allen key (i.e. hexagonal wrench) by removing and re-inserting four hex-head screws using the supplied key. The set consists of a wooden block measuring 22 cm x 10 cm (about 8.5" x 4") with four screws which thread into permanently fixed, threaded receptacles. The board also has two insets; one for holding the Allen key and one for holding the screws once they've been removed.
NOTE: do not overtighten the screws as this may result in the threaded receptacles being removed from the block when unscrewing.