Two markings on the guidewire: "I" indicates that the guidewire is located at the distal end of the needle, and "II" indicates that a distal barb is provided. Standard marking cannula on the guidewire: Used as a marking for surgeons during resection, starting at 3 cm away from the distal end. Skin fixation clamp: Prevent the guidewire from moving during patient transport. Echo tip of outer cannula, with depth marking (cm): Easy to determine the needle insertion position.