Limited edition of 5,000.
"Empire Strikes Back" details.
Released again in 2018 as just Boba Fett, number 41629, but with "Return of the Jedi" details.
From the NYCC Exhibitor page on Facebook:
An amazing new LEGO Star Wars BrickHeadz exclusive is coming to NYCC and it's one you're definitely not going to want to miss! Individually numbered and produced in very limited quantities this set will be one of the most desirable not to mention toughest of all exclusives to hunt down!
The only way to buy this 329 piece $40 set is via entering the lottery, and picking up in person at NYCC; unfortunately the chance to enter the lottery ended on Thursday [September 28, 2017].