My only real complaint with the Rival 650’s design is, as usual, a button placement. The idea is you can adjust the mouse’s center of gravity by adding, say, two weights to the front-left side, or one in each of the rear slots. SteelSeries includes eight removable 4 gram weights with the Rival 650, boasting 256 possible combinations.
That’s not immediately evident when you look at the Rival 650, but both the left and right panels are attached magnetically, with the light ribbons demarcating the edges. There are also rubberized pads on the left and right sides to facilitate picking up the mouse, without being too prominent. This is the most successful implementation I’ve seen from SteelSeries though, mimicking the flanged left and right mouse buttons from Razer’s DeathAdder and featuring a gently sloped right edge with plenty of room to rest my ring finger and pinky. SteelSeries leans heavily on the standard right-handed scoop shape for almost all its mice, the Rival 650 included.
