Which type of relay is used as time delay relays?

"Generally speaking, the delay performance of the time relay can be adjusted within the range of design, so as to facilitate the adjustment of its delay time. In addition, a time relay alone may not be able to do close. After closing for a period of time, it will open again. It is a cycle of time-delay closing and opening. However, configuring a certain number of time relays and intermediate relays can do it."(source: https://www.apogeeweb.net/electron/time-delay-relay-basics.html). After read it, someting still confused me: is time relay a normal type electrical relay? or Which type of relay is used as time delay relays?

2017-04-11T00:37:33.809Z