The men's 4 × 400 metres event at the
2015 Asian Athletics Championships
The 21st Asian Athletics Championships was held at the Wuhan Sports Center in Wuhan, China from 3–7 June 2015.Relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
Relays at the Asian Athletics Championships