Pipe Case Humidifier
This nifty little humidifier keeps my pipe case at around 60% humidity during dry Canadian winters. It also comes with a hygrometer to provide you with the relative humidity and temperature in your pipe case. Refill the humidifier with water as it dries and visibly shrinks. The humidifier and the hygrometer can both be affixed to the sides or top of your case as you choose. The gels inside the humidifier seem to last about a year, and then you need the recharge kit (below).