Xenith LLC, the football helmet and protective gear company owned by billionaire Dan Gilbert, now claims 10 percent market share of the helmet business and is closing in on producing 100,000 units annually at its southwest Detroit manufacturing facility. Xenith CEO Ryan Sullivan recently sat down with Crain's Senior Editor Chad Livengood to discuss the company's upward trajectory, the business impact of tariffs on Chinese-made parts for its helmets and what's next for the company as it branches off into other football protective gear and apparel.