The BOLL antibody targets the Boule-like protein (BOLL), an evolutionarily conserved RNA-binding protein belonging to the DAZ (Deleted in Azoospermia) family. Initially identified in *Drosophila* as essential for germ cell development, BOLL plays a critical role in meiosis and spermatogenesis across species, including humans. It regulates the translation of mRNAs required for spermatocyte progression through meiosis, particularly during the transition from diploid to haploid gametes. In mammals, BOLL is predominantly expressed in the testis, with mutations or dysregulation linked to male infertility, notably non-obstructive azoospermia. Research on BOLL has expanded to explore its diagnostic potential in assessing spermatogenic failure and its role in germ cell tumors. The BOLL antibody serves as a vital tool for detecting BOLL protein expression in studies of germ cell biology, fertility disorders, and reproductive toxicology. It enables applications like immunohistochemistry, Western blotting, and immunofluorescence to visualize BOLL's spatial-temporal expression patterns in testicular tissues or cell models. Recent studies also investigate BOLL's conservation in vertebrate development and its potential role in female fertility, though its primary characterization remains centered on male germ cell maturation.