Complex sentence: After Italy surrendered, guns captured by Germany were designated 9-cm Flak 41 (i) or 9-cm Flak 309/1 (i); some of these guns were used for the air defence of Germany and others were kept in Italy.
Split into simpler sentences: After Italy surrendered, guns captured by Germany forces were designated 9-cm Flak 41 (i) or 9-cm Flak 309/1 (i). Some of these guns were used for the air defence of Germany while others were kept in Italy.