This is a Martin string (3-set pack). I purchased it new at the end of November 2025, but I'm selling it because I won't be using it. It's new and unopened. At Soundhouse, it's 6540 yen (as of 2026/01/01). Light gauge acoustic guitar strings treated with long-life Lifespan 2.0 processing. - Brand: Martin - Model: MA540TPK3 - Type: Lifespan 2.0 Treated Phosphor Bronze - Gauge: Light (12-54) 3 sets - Features: Long-lasting, without sacrificing tone and feel - Output Characteristics: Enhanced output across all frequencies, resulting in a fuller, more balanced tone Thank you for looking.