12.4mm

 
The image shows a pool cue shaft. There are three sections of the cue shaft displayed, each with a different view. The top part shows the threaded end of the shaft, which is designed to be attached to the cue butt. The middle part of the image shows the shaft in full, featuring a sleek black design with the logo "REVO" near the base. The bottom part shows the tip of the shaft, which is colored yellow, indicating the area of impact with the cue ball. The background is white, highlighting the product.