What problems does it solve? Using this step-up ring, you won't require the base ring, which comes with Magnetic VND System; for example, if you want to mount 82mm Magnetic VND on your 67mm lens thread previously, you require a 67-82mm step-up + 82mm base ring on this new step-up ring you do not require that base ring anymore as step-up ring act as a base ring.
Built: Made of CNC machined aluminum with black color to avoid any reflection or leakage during your photography.
How do I find my filter thread size? Your lens thread size will be printed underneath your lens cap or written somewhere on the lens barrel. Please do make sure to order the correct size otherwise, it will not fit on your camera lens."