GenTran R301060 30-Amp 10-Circuit Outdoor Generator Transfer Switch for Generators up to 7500 Watts UL Listed and meets National Electrical Code requirements Can be expanded to up to 16 circuits - just upgrade it instead of replacing it! Uses standard, off the shelf circuit breakers for easy replacement or expansion Aluminum construction won't rust and is suitable for salt-water environments Accommodates arc-fault and GFCI breakers required by come jurisdictions to meet new NEC requirements