Exoglycosidase that cleaves the single beta-linked mannose residue from the non-reducing end of all N-linked glycoprotein oligosaccharides. {ECO:0000305|PubMed:12890191, ECO:0000305|PubMed:30552791}. This is the function of Ensembl gene identifier ENSG00000109323 (MANBA, mannosidase beta).