Large bore capacity with o-ring seal design. The most economical gear coupling design. Curved face teeth (sizes 1 through 7) for up to 1.5 degrees static misalignment capability. Series H coupling sleeves will bolt to all competitor couplings sizes 1 through 7 for interchangability in flex halves. Precision-drilled flange bolt holes with special body-fitting, grade 5 bolts for a long-lasting piloted flange connection.