Over- / Under-Voltage Relays TTG7000
The TTG7000 series of relays are designed to check voltages on AC networks.  There are many variants:

Single-phase overvoltage (ANSI 59 or 59N)
TTG7011 (instantaneous), TTG7111 (time delay)

Single-phase undervoltage (ANSI 27), also trip when auxiliary power is lost
TTG7012 (instantaneous), TTG7112 (time delay)

Undervoltage (for detecting induction motor flux decay before reclosure, ANSI 27)
TTG7013 (instantaneous), TTG7113 (time delay)

Two-phase undervoltage (ANSI 27) with 1 output relay
TTG7023 (instantaneous), TTG7123 (time delay)

...with 2 output relays
TTG7025 (instantaneous), TTG7125 (time delay)

Three-phase undervoltage (ANSI 27), also trip when auxiliary power is lost
TTG7032 (instantaneous), TTG7132 (time delay)

Three-phase undervoltage (ANSI 27)
TTG7033 (instantaneous), TTG7133 (time delay)

Three-phase time-delayed over- and under- voltage with four output contacts (ANSI 27 / 59)

See the homepage for Static relays for the full brochure.