Super strong C-clamp with deep jaws. Ideal for fixing welding, heavy steel plates, etc. The screw threads can be opened and closed smoothly by hand. The entire unit has been cleaned and greased. The main dimensions of the general "C-4 100mm" clamp are as follows. Basic dimensions (目安) Maximum opening: Approx. 100mm - 103mm Throat depth: Approximately 100mm - 112mm - Model: Deep Throat C-4 100mm - Brand: Super Tool - Size: 100mm - Type: C-clamp Thank you for looking.