The Sennheiser CX 400BT True Wireless are sleek in-ears that resemble the Sennheiser MOMENTUM True Wireless 2 in look and performance. They have a similarly warm sound profile and can passively isolate as much noise as their ANC-equipped relative. If you prefer a different sound, their companion app offers both a graphic and parametric EQ to adjust them. However, they have a disappointing battery performance. Still, if you're looking for a pair of well-built and customizable truly wireless headphones, they're a solid choice.