Reverse polarity protection. Consumers sometimes accidentally plug the connectors in backwards, which in the past caused the charger to potentially fail. Combined with the alignment arrows, we added a layer of protection to the charger to indicate improper connection issues, while protecting the charger from potential damage. Dual circuit board protection. The new circuit board protects against overcharging and monitoring how energy is transferred to each cell or to indicate any charging errors. Battery charge indicator offers a visual reference for charging status. 25%/50%/75%/100%. The other great benefit is using the charger to test a battery level before use. Bonus feature! Connect the charger to the battery to display the current charge level, so you will always know where your battery charge is at prior to use. Aligning the male and female connectors can be a little tricky, especially in low light conditions. So we added bright white alignment arrows to all of our connectors. This added feature will be a huge help with convenience and potential reverse connection issues.