XTR = Extra. Worth more than $500 IMHO, but what do I know. It has meaning in my eyes, anyway.
Unless you really need the money, there seems no reason to sell LLL.mobis now. It always is a risk walking away from a sale, the market could fizzle tomorrow, but the growth in LLL.mobis seems to have a lot behind it and you could kick yourself for selling in a few months/years. At least consider holding on to it.