System/Library/Frameworks/Foundation.framework
NSUnitSpeed.h
@interface NSUnitSpeed : NSDimension <NSSecureCoding>
@property (class, nonatomic, readonly) BOOL supportsRegionalPreference;
@property (class, readonly, copy) NSUnitSpeed *metersPerSecond;
@property (class, readonly, copy) NSUnitSpeed *kilometersPerHour;
@property (class, readonly, copy) NSUnitSpeed *milesPerHour;
@property (class, readonly, copy) NSUnitSpeed *knots;
@property (class, readonly) BOOL supportsSecureCoding;
+ (void)initialize;
+ (id)icuType;
+ (id)baseUnit;
@end