The Stretto Violin and Viola Humidifier with Digital Hygrometer is a complete humidification system for your cello. It is critical to protect fine instruments from changes in humidity, be it when travelling, making the trip from home to the performance venue, or simply adapting to changes in the weather and season. The Stretto family of humidifiers is designed instrument to instrument to afford a perfect environment for yours. Stretto products offer ideal protection for any string instrument.