ITSwitch is a simple and lightweight replica of iOS 7 UISwitch for Mac OS X.

Not much to it, simply set the custom class of a NSView to ITSwitch in Interface Builder.
You can create an IBAction and simply connect the two in Interface Builder.
Or you can use Cocoa Bindings to directly bind it to one of your properties:

[switch bind:@"checked" toObject:self withKeyPath:@"prop" options:nil];

Use these two properties to explicitely mutate the switches state:

/**
 *  @property checked - Gets or sets the switches state
 */
@property (nonatomic, assign) IBInspectable BOOL checked;

/**
 *  @property tintColor - Gets or sets the switches tint
 */
@property (nonatomic, strong) IBInspectable NSColor *tintColor;

Since ITSwitch uses its CALayer to draw a drop-shadow, you should also layer-back it's superview. If you don't use Core Animation, you can also simply embed the view in a layer-backed view.

ITSwitch requires 10.9+ and linking against the QuartzCore.framework.

You may want to consider setting the width of the view to the golden ratio * height.

So for example:

height = 20;
width = height * 1.618;