2-way humidity control refills for starter kits

B49 Refills for Guitars & Other Wooden Instruments

Rated 4.7 out of 5 stars
35 Reviews
Starting at $19.99

Pack Quantity

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Replace your Boveda every (three) 3 months. Just slip these refills into the Boveda Leakproof Holder(s) and slide them back into your instrument case. Set up a subscription to get replacements auto-shipped to you, so there's no lapse in humidity protection for your wooden instrument.



Using Boveda to balance humidity in an instrument case:

  • Requires zero maintenance—no more filling messy hoses and snakes and wetting sponges
  • Maintains an ideal relative humidity range for instruments—40-60% RH
  • Prevents wide fluctuations in humidity that cause the wood to expand or shrink, and degrade its performance abilities



  • ALWAYS insert Boveda into a leakproof holder before using in your instrument case. The holder acts as a liquid barrier if a packet is accidentally punctured while extending the life of your Boveda packets. The patented interior material allows water vapor to pass through to your instrument. The exterior is soft, like a polishing cloth, so it doesn’t scratch the finish.
  • DO NOT mix different Boveda RH levels within the same instrument case. 
  • DO NOT use other humidification products with Boveda in the same case because they will fight against each other and reduce the efficiency of Boveda.


  1. Slip the Boveda pack into the pouch of its leakproof holder. (DO NOT OPEN the Boveda itself.)
  2. Place in the case anywhere that allows for airflow and prevents puncture when you close the case:
    - Under the neck or headstock
    - On the strings

    - Open area in the case
  3. Close the case's lid. Always keep your case closed when using Boveda.


  • 4-Pack: Packaged in a resealable high-barrier heavy-duty plastic bag with a zip closure. Each Boveda is not individually overwrapped. 
  • 20-Pack Brick: Packaged in a heavy-duty plastic bag that is resealable using its attached tape enclosure. Each Boveda is not individually overwrapped.

    Unopened, Boveda can last up to 2 years.


5.25"/13.34 cm x 3.5"/8.89 cm


Replace Boveda 2-way humidity packs every three (3) months.


Achieves and maintains a constant relative humidity (RH) range between 40% and 60%, the industry standard for wooden instruments.


Food-grade salt, purified water and a food-grade thickening agent sealed inside a leakproof membrane.

Our Customers Say

Rated 4.7 out of 5 stars
Based on 35 reviews
Total 5 star reviews: 30 Total 4 star reviews: 2 Total 3 star reviews: 2 Total 2 star reviews: 1 Total 1 star reviews: 0
91%would recommend this product
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35 reviews
  • WM
    W. Michael M.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    2 hours ago
    Boveda-these humidifiers are the bomb!

    Love the humidifiers.! My Luthier has been after me for years to use humidifiers for my acoustic guitars. Finally, an easy application that works and is affordable.

  • CE
    Carol E.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    2 months ago

    Boveda humidifier packs are indispensable for keeping my cello healthy year-round, especially in the dry winter months (otherwise its voice gets real scratchy). Here's how I arrange them when my cello is in its case.

  • KH
    Kevin H.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    6 months ago
    Perfect Humidity Moderation

    Before I used Boveda case packs, my guitar action changed with the fluctuation in humidity. Now, my case stays between 47%-53%. The high temp you see on the hygrometer is from carrying it in my pocket! The low temp and humidity is from a time when I played outside and the case was open. The internal sensor in my guitar shows how consistently happy it is since Boveca!

  • KD Profile picture for Kenneth D.
    Kenneth D.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 year ago
    Conditioning Cases Prolongs Boveda Effectiveness

    Only 2nd purch of the 20-pack. I have a few acoustics. My Bovedas last about a year. I pre-conditioned all my cases and run humidifiers in the cold dry season.

    I also use Boveda for cannabis and my jug of Orville Redenbacker popcorn.

    D'Addario offers a two-way Boveda-based system. They do not offer, nor do they tell purchasers the necessity of Case Conditioning. Musicians who don't condition their cases complain that the Bovedas get hard in just a few weeks unlike mine which are lasting 52 weeks and most packs still not hardened (with only some hardening apparent.)

  • WJ
    William J Winward J.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 hour ago
    Thank you

    Glad I have something trustworthy for my guitar.

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