Proxxon parallel supports are ground in pairs. Its levelled surface helps to adjust work on drilling machine, lathes and milling machines. Made of high alloy, hardened steel 58-62 HRC. Parallel accuracy 0.002mm. 2 each of 8x10mm,15mm,20mm,25mm,30mm,35mm and 40mm. Length 100mm, Supplied in sturdy wooden box.