Semantron of Karakalou
The semantron or semandron (Greek: σήμαντρον), or semanterion (σημαντήριον), also called a xylon (ξύλον) (Romanian: toacă; Russian: било, bilo; Bulgarian, Macedonian and Serbian: клепало, klepalo) is a percussion instrument used in monasteries to summon the monastics to prayer or at the start of a procession. This is how it sounds in the monastery of Docheiariou in 2013 (recording by Wim Voogd)
Semantron of Skiti Anna (with pilgrims Jit + Jac)
Again Karakalou with some other instrument to get the attention of monks and pilgrims .