The 286 on delay and 287 off delay are square base, bladed versions of 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 and externally adjustable versions are available. The package on this series is typically socket mounted. It can also be panel mounted allowing direct connections to terminals with quick-connects or soldering.