Bought for a 1991 Miata track car to save weight. It's phenomenal how small the battery is and you wouldn't believe it would ever work in a car, but the little Miata starts up with no problem at all. Plenty of juice to turn it over. We left this battery in the entire summer as the car is a street car and track car. At first, I thought this battery would only work at the track, and wouldn't have the juice to be left in. I was wrong. It's been in all summer, driving to and from tracks many hours away, and driven in a daily driver environment with load(radio, phone charger, wipers, etc.). We never used a battery tender or anything else. The 1 and only time the battery ran out of juice was when my brother had the car off, and was charging his phone, and had the radio on in the car for over an hour. It simply doesn't have that reserve(obviously). I paired this battery with the XS Power 586 Tall Brass Post Adaptor (M6 Thread) which worked great with the OEM Miata battery adapters.6/7/18: Battery has performed flawlessly as a full time daily driver battery. This Miata is driven to and from work on a daily basis, and the car is driven to and from the track. Battery still turns over just like new. It even performed perfectly fine in the winter. This battery is perfectly fine to use as an every day daily driver, lightweight battery from my experience.2/21/19: The same original battery is still in the car. Still on a NASA TTE regional championship winning car, that is still daily driven to work, and everywhere else. The car started right up even in below zero conditions....no battery render or anything special. Battery is used just like OEM, and performing awesomely.3/30/19:Battery no longer has enough juice to start the car when it is below freezing. However it still starts fine in warmer conditions. Battery is likely reaching the end of it's lifespan, and will be replaced before next winter, however it is still starting fine in warm conditions. Very admirable run for such a tiny battery in a car that is driven as a daily driver and doubles as a NASA regional champion time trial car.