Most active towards p-nitrophenyl-N-acetyl-beta-D-glucosaminide(PNP-beta-GlcNAc) and diacetylchitobiose. Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. Optimum pH is 7.5. Optimum temperature is 37 degrees Celsius. Belongs to the glycosyl hydrolase 3 family.