The Guardline Wireless Intercom System is a super easy to use intercom system that allows whole home or office communication wirelessly! Set up takes under two minutes. The system comes with two base stations but you can expand up to 16 base stations for a complete communication network. Use four AA batteries (standard or rechargeable) to power your intercoms or use the included 9V power adaptors to plug into a wall outlet. The base stations are wall mountable or can be placed on any counter. Two year manufacturer's warranty and backed by exceptional USA-based tech support. We're a Seattle WA small business, in business since 1999, and we're super passionate about the products we've developed!