I was with my accommodation since 2006 (wood house) and I replaced the EXTEL these KIDDE. Easy to install batteries with long life ....... announced until 2019 I bought 3: AMAZON was out and announced an end next February, I received a lot faster. Packaging far too important to the size of the items (recurring reproach!) Instructions for explicit poses for both horizontal and vertical installation. One complaint: I find them a little big.