The Ace 31189 3 Way Socket with Removable Knob is a versatile bulb holder designed for use with three-way connectors. The removable knob allows for easy installation and replacement of light bulbs. Made by the trusted brand ACE, this model (Ace 31189) is a reliable choice for maintaining your lighting system's functionality. Whether you are a collector or looking to upgrade your lighting parts, this product offers a convenient solution for your needs.