Mitel Superset 4001 Single-Line Phone (Light Grey/Refurbished)The Mitel Superset 4001 Single Line Phone is a digital single line telephone that has an enhanced design and functionality. This phone works with the SX 200 ML EL or the SX 2000. Key Features: Speed Dialing Conference Call Set Up Ability Send Receive Call Forward, Call Hold (Place Retrieve), and Call Transfer Last Number Redial Do Not Disturb Large Message Waiting Lamp Wall Mount 7 Programmable Keys Volume Control Hold Button Handset Handset Cord Line