... Nut: SD6/10/16/25-LM -Matched Holder: ER type -SCM-440 material -Heated jaw ZHY CNC ToolsWe are ... Wrench Hand Tool: type A, type M, type UM.2.Using SCM-440 material, with heated jaw, have high hardness and toughness. ... 3.It is used to tool holders, to tighten the tool.4.ER A type hand ... i will reply you at once, thank you! ZHY High Precision M And UM Type ER Wrench Hand Tool