Complex sentence: Along with numerous smaller uninhabited offshore islets (the largest of which are Sýrna and Ofidoussa), it forms the Municipality of Astypalaia, which is part of the Kalymnos regional unit.
Split into simpler sentences: Along with numerous smaller uninhabited offshore islets (the largest of which are Sýrna and Ofidoussa), it forms the Municipality of Astypalaia. Astypalaia is part of the Kalymnos regional unit.