1.   She slotted in a fresh filter.

2.   In February, panic-stricken Israelis rushed to exchange gas masks for newer models with fresh filters.

3.   Since the war, Israelis have been changing their masks periodically for new models with fresh filters.

4.   Since the war, Israelis have from time to time exchanged their gas masks for newer models with fresh filters.

5.   With tensions growing in the Gulf, Israelis have been asked in recent weeks to exchange their old models for new ones with fresh filters.