The correct height rings you need for a Vortex Diamondback 4-16x42mm Scope you depend on the rifle and base you are mounting it to. The Vortex Diamondback 4-16x42mm scope has an objective lens outside diameter of 2.0" so you will want a set of 1" diameter rings with a centerline height of around 1" for most bolt action rifles. The guide below will help determine what ring height your need.
https://www.opticsplanet.com/howto/how-to-how-to-measure-scope-height-scope-ring-height.html
Because I do not know what rifle you intend to mount your scope to, I cannot confirm compatibility. But for a general reference, a 40-42mm objective lens on a bolt gun will typically work with low-height rings.