G crochet hook is equivalent to a 4.0 mm size hook. The G hook is often used to make bulky, chunky yarns and thicker stitches. This size of hook is great for winter garments or any larger-scale project that needs a nice, solid stitch. The 4.0 mm size hook is also a great size for working with bulky or super-bulky weight yarns that require a larger stitch size, as well as some of the other unusual materials available such as ribbon, cord, etc. You can also use this size hook to create handles for bags or other accessories that require a thick, sturdy handle.