The Blur suit was an outfit worn by Clark Kent, during his time as the "Blur".
The first Blur suit was actually just the clothes he wore, when Henry James Olsen took the first photo of Clark, saving someone. This outfit consisted of a red jacket, blue T-shirt and blue jeans.
Oliver Queen Variant
To protect Clark's identity, Oliver Queen donned an outfit, to pose as the "Red-Blue Blur". This outfit consisted of a blue, hooded leather jacket, black domino mask, yellow belt, blue jeans and a red cape. For unknown reasons, Clark never chose to don this outfit himself.
Following the death of Henry James Olsen, Clark donned a new outfit. This new outfit was all-black, causing his alias to be changed from the "Red-Blue Blur" to just "the Blur". This new outfit consisted of a black trenchcoat, black pants and a black T-shirt. On this new outfit, Clark chose to sport the House of El symbol on the chest.
Due to rising paranoia among the public and the U.S. military, Clark chose to abandon his all-black outfit and returned to a colorfull outfit. Like his first outfit, this new one included a blue T-shirt and blue jeans. The main part of the outfit was a red leather jacket, that sported the House of El symbol on the chest. At one point, Lois attempted to upgrade the suit with a hood and sunglasses (to better protect Clark's identity), but these changes were rejected by Clark, due to the problems that they'd cause (the hood wouldn't stay on during super speed and the sunglasses would make it difficult for him to see at night). Clark would ultimately abandon this outfit for the first Superman suit.