Because it has no zipper. Bose QC35 replaces the head beam cover, you need to remove half of the headphones and remove the old head beam sponge, and then use the soldering iron to solder the wire from the circuit board (about ten screws and six solder wires), then you need to remove the wire Go through the middle of the head beam sponge, fix the two ends of the head beam, then weld the wire and install the head beam and headphone sleeve!
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