The built-in indicator lights will light up when there's an issue with a fuse, but remain off if everything is normally. This built-in functionality allows you to easily identify issues with the fuses with minimal effort! This ground distribution block is perfect for cars, campers, solar panels, batteries, ATV, UTVs, caravans, boats, trailers, marine, stereos and countless other applications. The contact connectors are sand nickel-plated and do not fade over time. The removable plastic shell helps protect the unit from outside environment and greatly extends its lifetime and longevity. If you experience any issues with your order or the connectors you receive, reach out to our customer service team for help! With a 30-day money back guarantee and free support from our team, you've got nothing to lose. Start your next project by purchasing the best power distribution fuse block available on Amazon! *Some minor scuffing/scratching can occur on the plastic cover during the manufacturing and shipping process.