The Howard Core HT1 Humitron Humidifier functions as a protection for your violin or viola. Within the green tube is a long sponge that will feed humidity to your instrument when damp.
Simply wet the humidifier with water and wipe off excess dripping, then store it in the F-Hole of the instrument. Fits 1/2 violins up to full-sized violins and violas.
Keeping your violin or viola in stable humidity prevents cracking and the opening of the seams of the instrument. Humidification is a fundamental maintenance habit that will keep your instrument in good playing condition.