The SFA-101 is a hold-down clip designed for DIN rail snap-mount sockets used with IDEC relays and timers. It is compatible with multiple socket types including SH1B-05, SH2B-05, SH3B-05, SH4B-05, SY2S-05, and SY4S-05, providing mechanical retention for relays such as RH1B, RH2B, RH3B, RH4B, RY2S, and RY4S series. The clip ensures secure mounting and prevents accidental socket displacement during operation. It is commonly used in industrial control panels and automation systems where reliable relay retention is critical.