The 326 on delay and 327 off delay are “octal” base constructed time delay relays. Both AC and DC versions are available. On delays can have up to three poles. The timing circuit is a fully encapsulated precision RC (resistor – capacitor) network typically used in applications where oscillators are not desired. Fixed time versions are available. Single pole and double pole versions have 8 pin bases. The 3 pole version has 11 pins. All are intended for socket mounting.