The parties to this trademark dispute make consumer products for rinsing sinus cavities. Med-Systems, Inc., the earlier entrant in this market, sells its products under the federally registered trademark SinuCleanse and two similar marks. Water Pik, Inc., which traditionally sold oral irrigators and showerheads, registered the trademark SINUSENSE with the intention of selling sinus-irrigation devices under the brand name “SinuSense.” It brought an action against Med-Systems in the United States District Court for the District of Colorado, seeking a declaratory judgment that its use of the SinuSense brand name did not infringe on any of Med-Systems’ marks. Med-Systems counterclaimed for trademark infringement and unfair competition under the Lanham Act, 15 U.S.C. §§ 1051–1127. Ruling that the SinuSense brand was not likely to cause consumer confusion, the district court awarded summary judgment to Water Pik on the counterclaims and dismissed Water Pik’s declaratory-judgment claim as moot. We affirm.