SINAMICS G120X IP21 top cover for FSC and FSD Supplementary system component IP21 Top Cover for the SINAMICS G120X frequency converter. With the optional IP21 Top Cover, the SINAMICS G120X converter for frame sizes FSA to FSG achieves protection type IP21, making it suitable for use even outside a control cabinet, such as in lockable equipment rooms. With wall mounting, the IP21 Top Cover is mounted above the converter. SINAMICS – simply my drive.