This 30A AC Main Breaker Panel combines the functions of a circuit master switch and circuit protection in one unit, with 1 pre-installed 30A double-pole circuit breaker (need to be switched together), 3 15-amp AC circuit breakers for branch circuits, 3 additional empty slots, and 14 frequently used tabs for expanding your circuits as needed. Panel features red reverse polarity LEDs and green LEDs to clearly indicate if the switch is on or not, making it easy to observe breaker status; all hot, neutral, and safety ground buses are installed and fully pre-wired. The breaker panel is made of rust-resistant material, which prevents the panel from rusting and prolongs its service life; The night backlight design makes it easier for you to read and operate the product. Provide AC power protection for your marine electrical system, safer to use. Ideal for boats, yachts, RVs, etc.