Hardened and ground steel parallels for workshop use. Supplied in pairs for packing or levelling components prior to machining in tool rooms or machine shops. Supplied in Pairs. Hardness: HRC:58 - 62 Accuracy: ±0.005mm 16 Piece Set Contents: eight pairs of the following sizes: 5 x 16 x 100mm, 6 x 18 x 100mm, 8 x 24 x 100mm, 10 x 30 x 100mm, 12 x 36 x 150mm, 14 x 48 x 150mm, 18 x 60 x 150mm, 22 x 62 x 150mm. And support blocks.