Helical Products Co. (Santa Maria, CA) introduced single-piece, flexible couplings to compensate for mechanical movement irregularities. The units require neither maintenance nor lubrication; they offer constant rotational velocity, smooth bearing loads, and feature no backlash. Outside diameters (OD) range from 3/8 to 3". Metric OD of 15, 20, 25, 30, 40, and 50 mm are available. Imperial and metric bore sizes may be combined. The units are available in aluminum or stainless steel.