Ever BambooGuitar Dehumidifier Bag Set w/ Bamboo Charcoal 1 Pack black EB1309

Is it safe to lay the packets directly on my instrument?

How do you know when it’s time to recharge these?

What is the actual length & width of the bag & bamboo? Not sure these will fit in my case.

Can these be put inside the guitar itself(through the sound hole)? will it damage the guitar in any way?