The patient who is afflicted by a superficial vein problem is quite different than the patient afflicted by a deep vein problem. And the difference is obvious. The superficial veins are fairly visible normally. And so a patient who presents with an isolated problem of a shallow veins can actually describe and can show you what he's having. Meaning, well, this vein feels hard and is red. And I feel that redness from my knee to here cause everything else is normal and so forth. And so these problems are much more straightforward than the problems that affect your deep veins. In the sense that the symptoms and the signs are visible to the clinician. And you really do need still confirmatory testing, but not to assess the area that is affected because it's fairly obvious, but also to assess the other veins and make sure that this is not just an isolated problem to the shallow veins, but also that it's not affecting the deep veins because that's something you cannot see. I mean, God forbid that patient has a clot in the shallow veins and the deep veins, and the only way to see the deep veins is going to be with an ultrasound. And so that's why it's needed.