Enables beta-N-acetylglucosaminidase activity. Involved in N-glycan processing; brain development; and rhodopsin biosynthetic process. Located in late endosome and plasma membrane. Colocalizes with Golgi apparatus and endoplasmic reticulum. Is expressed in adult head. Human ortholog(s) of this gene implicated in Sandhoff disease; Tay-Sachs disease; and spinal muscular atrophy. Orthologous to human HEXA (hexosaminidase subunit alpha) and HEXB (hexosaminidase subunit beta).