Enables cysteine-type endopeptidase inhibitor activity and serine-type endopeptidase inhibitor activity. Predicted to be located in extracellular space. Expressed in several structures, including anal sphincter muscle; cuticle; epithelial cell; intestine; and phasmid neurons. Used to study familial encephalopathy with neuroserpin inclusion bodies. Human ortholog(s) of this gene implicated in several diseases, including Alzheimer's disease; artery disease (multiple); autoimmune disease (multiple); and lung disease (multiple). Is an ortholog of human SERPINI1 (serpin family I member 1) and SERPINI2 (serpin family I member 2).