KEY FEATURES- Machined from Copper, Giving You a Durable and Steady Experience even with Heavy Telephoto Uses Aluminum Oxidation Technology to Achieve high-end Matte Surface Treatment Features a Super Elegant, Light, Portable, Professional and Compact Design Designed with built-in Gilded Electric Pins to Ensure Accurate TTL metering and AF function Consists of 12 mm, 20mm and 36mm tubes, which can be used individually or in combination for seven different possibilities