For a Yamaha yz250fx...Lighter than stock. More cca than stock. Cheaper (on sale) than stock. Not the same size as stock but still fit well, without need for modification or use of the extra "feet" they provide, which wouldn't have worked bc of their orientation on the base. Had to bend the tabs on the bike's connectors, but that's nbd. Also had to reuse oem hardware bc I didn't want to drill out the hole in the connectors. Sounds bad but it's not. One of the easiest aftermarket item installs ever.