The storage of oxygen sensors requires a high level of technical effort, but is necessary because they are subject to natural wear and tear even if they are not used. NRC sensors are quasi-shock-frozen, interrupting natural wear and bringing back to a normal temperature before actual use. This is the only way to achieve really long service lives and precise analyses. Finally, they are shipped in airtight aluminum cans, which drastically reduces wear and tear during shipping. So you can always rely on fresh goods.