Check the listing for details. Blackstar Polar 4 4-channel Guitar Interface. Condition: New. Listed at 379.99 USD. Guitar Recording Made Easy Tailor-made for guitar players, the Blackstar Polar 4 is an audio interface designed to make the recording process easier. The Polar 4 includes four FET-based input channels, which are armed with 81-inspired microphone preamps and +48V phantom power. Moreover, you get per-channel Enhance switches that activate a clip-proof input setting, along with an amp-like feel for instruments and added air and clarity for microphones. The Polar 4 includes two headphone outputs and four line-level outputs, which make achieving studio-quality monitoring easy. Complete with an excellent complementary software bundle, the Blackstar Polar 4 is a capable audio interface that effectively overcomes the typical challenges of guitar recording.