Boveda B49-70-4P

Only Boveda’s patented 2-way humidity control adds or removes moisture to balance fluctuating humidity during seasonal changes and travel to maintain the ideal humidity level in your guitar, violin, cello and other wood and wooden wind instrument cases. This 4-pack will replenish your Boveda 2-way Humidifier so you can keep your instrument healthy and prevent warping, cracking, buzzing, shrinking, and expansion.