This is used by attaching between camera body and lensof the 35mm single-lens reflex camera.It comes as a setof 3 tubes of different lengths which singly or in combination makes it usable in 7 different lengths. It couples perfectly with the camera"s automatic diaphragm. With cameras of TTL.AE(Through-the-Lens,Automatic.Exposure)type it gives perfect coupling except when combined with electronic flash AE unit. Features: Macro Extension Tube Set For Nikon SLR and Nikkor AF, AF-S, D, G and VR lens series.new and high quality The AF Extension Tube Set can transform your Lens into a Macro Lens.This is used by attaching between camera body and lens of the 35mm single-lens reflex camera. It couples perfectly with the camera"s automatic diaphragm. Tube diameter : ab.69mm. Tube Lengths: (1) 12mm.(2) 20mm.(3)36mm. This extension tube consists of 5 parts: 12mm tube, 20mm tube, 36mm tube, Front Cap, Rear Cap. Material: Brass Chromed and ABS(Acrylonitrile Butadiene Styrene), color : black Package Contents 1 x Neewer 3-Piece Macro Extension Tube Set For Nikon