Commlite Colorful Metal TTL Auto Focus AF Macro Extension Tube Ring for Canon EOS EF EF-S 60D 7D 5D II 550D Blue Support accurate TTL & Autofocus. Built-in electric pins. Compatible with all EF and EF-S Canon lenses. Combined of 3 tubes with different length of: 13mm, 21mm, 31mm. Made of high-quality Aluminum material that is stronger. Upgraded circuitry to work better with digital SLRs cameras and SLR lenses.