Christmas gifts from sales reps and front office folk...it's nice to be understood and appreciated.
That little black ball was part of the Elijah Craig gift set; pour water into the small hole on top & freeze. When you're ready to pour, pop it open and out comes a nice, flat bottomed cube that fits perfectly in the bottom of the included glass. Hadn't seen one before, but it works as advertised...even if I did start with the Bulleit.