The DL4 by Line 6, introduced in 1999, is one of the first digital modeling effects units. The DL4 features models of 16 vintage delay effects, including the Echoplex, Roland Corporation's Space Echo, and the Electro-Harmonix Deluxe Memory Man. It is also used for looping. According to a May/June 2000 review in Canadian Musician, it "delivers a cavalcade of features for a reasonable price."
References
Line 6 DL4 Wikipedia(Text) CC BY-SA