Predicted to enable serine-type endopeptidase inhibitor activity. Predicted to act upstream of or within negative regulation of peptidase activity. Predicted to be located in extracellular region and membrane. Predicted to be integral component of membrane. Is expressed in epididymis and testis. Orthologous to human WFDC8 (WAP four-disulfide core domain 8). [provided by Alliance of Genome Resources, Apr 2022]