The SL button refers to the left shoulder button on the Joy-Con, when it is detached from the Nintendo Switch. The wrist strap that comes with the Joy-Con can be attached to make the button easier to press. It serves as an equivalent to the L button, acting as a shoulder trigger. In Ultimate, it is used for grabbing opponents, much like how the L button is used for grabbing in Super Smash Bros. for Nintendo 3DS. It is present on both the Left and right Joy-Con controllers.
| Controllers and buttons | |
|---|---|
| Nintendo 64 controller |         
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| GameCube controller |           
|
| Wii Remote (and Nunchuk) |           
|
| Classic Controller | LR       
|
| Nintendo 3DS |            
|
| Wii U GamePad / Pro Controller | L R           
|
| Joy-Con |                
|
| Switch Pro Controller | LR
|
| Third-party controllers | Hori Mini Pad · Arcade controller · Keyboard |
| Other | Smash Controller · Controller modification |