Boveda High-Absorbency 49% Two-Way Humidity Control Pack for Music Instruments in Extreme Humidity – Single – Size 40 – Prevents Warping & Cracking of Wooden Instruments – Individually Wrapped

This is a good size for larger needs than the smaller packets. If you need to maintain 49% relative humidity then this is exactly what you need. The two way humidity control keeps the contents at 49%. Boveda is a leader in these two way humidity control packs so you know you can trust the accuracy.

Waste of money. Followed all instructions after emailing company for support. Doesnt work. Not even a little. Humidity started at 70%. After 4 weeks still at 70%.

Work ok I guess . Was expecting it to be more than one based on the listing.

This packet is larger than the ones bought at the shop. It does exactly what it's supposed to do. It has kept my stuff fresh and moist. I really loved how it came packaged inside another plastic wrapper making it stay gooey and fresh. I was able to put it into a bigger jar. So far has not disappointed. It helps to have a darker jar to keep light out too.

ギターケースに三個使用しています。湿度調整がうまくいっているようです。

開封後しばらく置いておくと本気出してきます。ジップロックに入れてしばらく放置後、校正したい物をその中に密閉すれば校正もスムーズにできます。温度変化の少ないところで観察してみましょう。