Component of the cuticles, which contributes to the formation of extracellular envelopes protecting the organism from the environment (PubMed:1864469) (Probable). Plays a role in alae formation in dauer larvae (PubMed:15936343, PubMed:30409788). Expressed in head and tail seam cells during dauer larva formation (PubMed:1864469, PubMed:15936343). In dauer phase larvae, expressed in two ribbons approximately 2 microns wide running along the lateral lines underneath the alae (PubMed:1864469). Not expressed in late embryogenesis or adults (PubMed:15936343). The small repeats A-A-P-[AVI] are also present in many proteins constituting the protective envelope of other species. RNAi-mediated knockdown results in no alae in dauer stage larvae, which results in a wider lateral cuticle and larger body diameter.