Fomito Auto Plastics Contact AF Macro Extension Tube Ring For CANON EOS EF DSLR & SLR Tube diameter : ab.69mm. Tube Lengths: (1) 13mm.(2) 21mm.(3)31mm Material: Brass Chromed mount + ABS(Acrylonitrile Butadiene Styrene) body This extension tube consists of 5 parts