This is a Chinese musical instrument called xun. Similar to the Japanese ocarina, this instrument is blown at the top like you blow a flute, and the pitch can be controlled by covering the finger holes. The 6cm smaller version has a higher pitch and it contains 6 fingerholes. The 8cm version has a slightly lower pitch and it contains 8 fingerholes. Here is a video showing an earlier version of it: https://www.youtube.com/watch?v=4vallobApQc