User manual Sennheiser PXC 550-II (English - 38 pages)
Review: Sennheiser's PXC 550 Wireless Headphones Should Put Bose on Notice - MacRumors
PXC550 won't hold >20% charge and runs out quickly. Cracked the case to check buttons and found an extra 'music' button. Anyone else had this issue? : r/sennheiser
Product overview
Sennheiser PXC 550 Wireless review: A full-size Bluetooth headphone with active noise canceling that rivals Bose QC35 - CNET
Sennheiser PXC 550 Review: Surprisingly Solid Bluetooth Headphones