First off, thanks for the compliments all!
Zman's got it... it's eggcrate. I have a firefish and a clown in there that I'm not big on losing, so I put it on there just for safety's sake.
I don't like it though... It cuts down on the lighting in the tank too much. I was thinking of taking a piece of acrylic and cutting a frame that fits into the inside rim, then stretching monofilament netting across and gluing it to the frame as a super lightweight cover to retard jumping. I haven't gotten to that yet.
Yep, that's the new K2 Viper. I upgraded to it not too long ago and I couldn't be happier. The only thing I'd recommend is buying it from somewhere that lets you upgrade the stock bulb from the JBJ to a Hamilton, XM, etc bulb. The JBJs have a record of early failure and mine was no exception. They replaced it in warranty but I was forced to set up a backup pendant I had for the week I was out of commission.
Oh yeah... it's the JBJ Nano. I upgraded from a 12DX, buying from a company that sells the tank and K2 viper in one package, so I never got a lid for it. It was sold with the intention to be used as shown.