Volt?

We went this morning for an ultrasound (no bloodwork) and we will be going back next week for another (with bloodwork). The doctor went all around and she only found one gestational sac, so it looks like one kiddo for us. Of course it is possible another one(s) could be hidden, but the chances are that we are having one this go around.
My nephew was trying to figure out names for our twins, and the only one that really works for a singleton is Volt (Surge Jr.). I think I will call it that for a while. Sherri and I already have the names picked out - Boy = Joel; Girl = Sarah; but for the next month we are having a Volt.
Here's a picture from the ultrasound. The dark blob is our kid. The doctor said she could see the yolk sac, but I couldn't.