AGM batteries

My Red-Top, Dry-cell technology Optima was new in year 2000.
I finally replaced it in year 2015.
Cheapest doggone battery I ever bought.
Heavy bugger too.... but just right to bolt down over my right rear wheel;
and to think, I bought it cuz it didn't need to be vented, and was thus legal to run in my trunk...... which now, by father time, is ventilated anyway, as rust.