The CT-ERS.21S is a single-function electronic time relay from the CT-S timer range. It provides an ON-delay (delay on make) function with 10 time ranges from 0.05 s to 300 h. This time relay operates with a rated control supply voltage of 24 - 240 V AC / DC and has a 2 c/o (SPDT) output with contacts rated at 250 V / 4 A. A sealable transparent cover for protection against unauthorized changes is available as accessory. The device offers screw connection technology with double-chamber cage connection terminals.