This is a beige "Sleekline Telephone" made by Southwestern Bell, model FC2556AM.
The phone measures approximately 8.5" tall, 2.75" wide, 3.75" deep, 9.5" long for the cord, and 69.25" long for the phone cable.
The sleekline telephone is in good pre-owned condition in the original box. It has not been tested and is being sold as-is.