OH-14 Case Plus Humidifier with OH-2 Digital Hygrometer Combo Pack. The Oasis OH-14 Case Plus Humidifier with OH-2 Digital Hygrometer Combo Pack is the solution for monitoring and controlling your guitar's health. It includes 2 essential componants. OH-14 Case Plus+ Humidifier The Oasis OH-14 Case Plus+ Humidifier uses the same evaporative membrane as the Oasis Plus+ humidifier (see our sku# 421671), providing 50% more daily humidity supply than the Oasis Case humidifier. This humidifier is designed for use in drier environments where the relative humidity is below 25%. The Oasis Case Plus+ humidifier, like the Oasis Case humidifier, uses two powerful small magnets, which are embedded in the seam of the humidifier, to attach to either a small sticky backed piece of stainless steel or a metal clip (both are provided with the humidifier). The Oasis Case Plus+ humidifier can be used in woodwind and stringed instrument cases such as clarinet, violin, cello, guitar or mandolin. Oasis Digital Hygrometer A guitar, or any other stringed musical instrument made of wood, is at risk of cracking when the relative humidity drops below 40%. The Oasis Digital Hygrometer accurately measures relative humidity and can help you decide when to use your Oasis Guitar Humidifier. Because relative humidity varies greatly, even inside your home, it's recommended that you keep your hygrometer close to your instrument. To get an accurate humidity reading for the guitar body, it's recommend that you first lay the guitar case with the back to the floor and open the cover. Take a small piece of cloth and place it under the hygrometer to avoid scratching the top of your guitar. Put the hygrometer on the guitar top with the sensor at the edge of the sound hole. Close the case and allow 4-6 hours for the humidity to stabilize. Open the case and look at the reading within a few seconds and you get the humidity reading that existed just before you opened the case. Because the Oasis humidifier will...