Blind operation type recording: Ballpoint pen type mechanical rebound switch. Press to start recording (pen hat lowers), then press again to end recording and save (pen hat rises). Multifunctional: Can record while writing for two-way recording. Pen refill can be replaced to function as a signature pen. Noise reduction: Uses an acoustic 8-core DSP noise reduction module to reduce environmental noise. Connection: Connect OTG adapter to manage and transfer files on phones. Supports Android and iOS, plug and play. Headphone compatible: Plug in headphones to play music and recording files. Supports inline headphone controls for song switching, fast forward/back, volume adjustment and file deletion. Material: Made with metal alloy using CNC process and baking paint electric transition for durability, oxidation and scratch resistance.