A vise includes a stationary jaw at one end of a rail and including a moveable jaw member having a clamping surface, and a lever having a cam at one end engaged with the jaw member; and a moveable jaw on the rail and including a moveable member engaging with a limit member at the other end of the rail; a jaw element having one end secured to the moveable member and having a clamping surface at the other end, an internal moveable wedge secured to the clamping surface of the jaw element and having first and second inclined surfaces; two opposite arms pivotably secured to the moveable member wherein one ends of the arms contact each other and engage with the first and second inclined surfaces respectively, and each arm has a cavity on an outer edge; and two urging blocks complimentarily engaging the arms respectively.