(Included in our Discounted Full-Service Package) The Sentrilock Lockbox is an electronic lockbox that only allows licensed agents to access the property. Normally, working in combination with using the Showing Time, showing service. Sentrilock boxes are the most secure way to allow agents into your property. The Sentrilock is hand-delivered and set up for you. (**These boxes must be returned to Mr. Lister after your house has sold.**) (Installation is subject to location and accessibility.)