Custom sized bottom bracket spacers for Italian thread applications. 6061 t6 aluminum, 36.1mm ID 41.25mm OD. I normally stock .5mm, 1mm, 1.5mm, 2mm and 2.5mm spacers. I can make any other thickness you may need within reason with a typical tolerance of +/- .05mm, for the same price. Please specify what thickness you need when ordering.