There is disclosed a pair of components which, in the embodiment described, are a tooth (2) and adaptor (3) for earth-moving apparatus (1). The adaptor is for mounting the tooth on an earth-moving bucket, this mounting being releasable to allow replacement of the tooth when worn. The components define aligned passages (11) through which a locking pin (12) extends to retain the components together. The locking pin has formations (22) for engaging formations (20) on the first component when the pin is rotated from a free position into a locked position. The pin has an insertion recess (27) which is aligned with the formations (20) allowing the pin, in the free position, to be inserted into, or removed from, the aligned passages. The formations (20) are resiliently movable to stably engage the pin when in the locked position.