A cartoon from Franco Tabacco
An iron pivot inserted into the head of a "boxer" during the first restoration (1970s and 1980s), got rusty, expanded and produced a crack into the head. Also note the chromatic alteration of the stone, due to an applied "protective" substance. From: Andreina Costanzi Cobau & Roberto Nardi, L'intervento di conservazione e restauro, Le sculture di Mont’e Prama–Conservazione e restauro" 2014, Gangemi editore, pp. 130-142. During the extensive restoration perfomed between 2007 and 2011, some of the pivots were removed, as well the altered protective substance previously applied on the few pieces exposed.