150J7 Poly-V rib belt. 7 Ribs. 15” (381mm) Pitch Length - PJ381 Metric belt. INDUSTRIAL GRADE “J” Series Poly-V (Micro V) ribbed belts are designed to replace OEM belts on extra heavy-duty applications such as 150J7 sander/planer belts, compressor belts, 150J7 (7-Rib PJ381) fitness drive belts, and electric motor drive belts. AKA: J7-150 Belt.