ERGOTRON 97-858-026 SV Sit-Stand Combo Extender, compatible with 45-260, 45-266, 45-270, 45-271, 45-272, 45-273 Sit-Stand Combo Arms°, Replaces Vertical Mount Base when installed, POLISHED ALUMINUM Add a durable, easy-to-clean exterior composed of aluminum, high-grade plastic extender to your SV Combo Arm and increase its reach by 9" (23 cm).