Canon Macrophoto Coupler FL 55mm brand_Lightware the numbers in brackets are

the numbers in brackets are approximate interior size in cm (diameter x depth)

just in case you're not into making too much of a show of it

ET-86 lens hood

The Mamiya RB67 is a big

which doesn’t affect viewfinder function but will prevent other accessories from mounting to the top of the viewfinder

Canon Macrophoto Coupler FL 55mm brand_Lightware the numbers in brackets areThe Canon Macrophoto Coupler FL 55mm is a lens reversing adjustable extension tube designed for macro use. You can use it directly on camera or on bellows its totally up to you. Attaches to FD FL cameras and lenses with 55mm filter threads. In excellent condition, with box. Lens, camera and bellows are sold separately.