Replacement Pack for Fretted and Bowed Instruments and Woodwinds | Individually Overwrapped

Boveda High-Absorbency 49% RH Single Size 40

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If you live in high humidity year-round, here's the solution to keep guitars and other wood instruments in the moisture safe zone. Tested in a lab at rainforest-like conditions! Absorbs 3x more moisture than Boveda 49% RH.

Using Boveda High-Absorbency in an instrument case:

  • Protects wood instruments from warping in year-round extreme humidity level of 50+% (Lower humidity? Shop Boveda 49% RH for wood instruments here.)
  • Staves off mildew build-up
  • Automatically maintains constant RH between 45% and 55%—the safe zone for wooden instruments
  • Prevents humidity fluctuation from going in and out of air-conditioned venues, playing outdoors or traveling by air

This single refills:

  • Directional Starter Kit or Single Fabric Holder for displaying and/or storing:
    • Acoustic guitar
    • Semi-hollow body guitar
    • Hybrid electric or acoustic guitar
    • Acoustic or electric bass guitar
    • Ukulele
    • Mandolin
    • Any string instrument with a center sound hole or port

  • Single Fabric Holder for storing:
    • Violin
    • Viola
    • Clarinet



  1. First remove the clear overwrap from the Boveda, then slip unwrapped Boveda into the pouch of its protective fabric holder. (Do not open the Boveda itself.)
  2. To learn where to place with your instrument, visit the FAQs for Placement of Boveda in Instrument Cases.

Always insert Boveda into a pouch of a Boveda fabric holder before placing in an instrument case. The fabric holder allows Boveda to last longer and work better and acts as a liquid barrier if a packet is accidentally punctured. 


  • Mix Boveda 49% RH High-Absorbency and Boveda 49% RH or different Boveda RH levels within the same instrument case.
  • Use Boveda in the same case with other humidification products because they will fight against each other and reduce the efficiency of Boveda.


  • To refill a Boveda Directional Fabric Holder: Use one (1) Boveda High-Absorbency 49%
  • To refill a Single Fabric Holder: Use one (1) Boveda High-Absorbency 49%
  • To refill a Boveda Double Fabric Holder: Use two (2) Boveda High-Absorbency 49%

Each Boveda is individually overwrapped. 

Boveda will last 1-6 months depending on the time of year, your climate and your case.
Unopened package: Up to two (2) years 

When Boveda 49% RH High Absorption expands, it’s time to replace the pack. Order a replacement pack BEFORE Boveda expands to avoid a lapse in humidity protection for an instrument in high humidity.

Achieves and maintains a constant relative humidity (RH) range between 45% and 55%.

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

Size 40: 5.25"/13.34 cm x 3.5”/8.89 cm

Our Customers Say

Rated 5.0 out of 5 stars
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100%would recommend this product
1 review
  • SJ
    Steven J.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    10 seconds ago
    High Efficacy

    The size 40 worked very well for use with my instruments, maintaining a stable humidity. Better even than using multiple packs of a smaller size. Great to have these!

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