The DL4 Delay Modeler by Line 6, introduced in 1999, is a digital delay pedal. It 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 also has a 14 second looping function. According to a May/June 2000 review in Canadian Musician, it "delivers a cavalcade of features for a reasonable price." In 2018, Pitchfork called it "quietly the most important guitar pedal of the last 20 years."