  A relational structure is called reversible iff every bijective endomorphism
of that structure is an automorphism. We give several equivalents of that
property in the class of disconnected binary structures and some its
subclasses. For example, roughly speaking and denoting the set of integers by
${\mathbb Z}$, a structure having reversible components is reversible iff its
components can not be "merged" by condensations (bijective homomorphisms) and
each ${\mathbb Z}$-sequence of condensations between different components must
be, in fact, a sequence of isomorphisms. We also give equivalents of
reversibility in some special classes of structures. For example, we
characterize CSB linear orders of a limit type and show that a disjoint union
of such linear orders is a reversible poset iff the corresponding sequence of
order types is finite-to-one.
