if you be like I , you be always shine light into people 's eye , ear , and mouth in clinic and on the ward . it be important when check pupillary reactivity to have a strong , even , consistent light that you can trust !  this light fit the bill perfectly . it clip into you whitecoat breast pocket and stay there . it come in several stylish color . and the ability to manually focus the light allow you to eliminate annoying ` hot spot ' and ` cold spot ' in the beam , common with cheap penlight , that might lead the naive medical student to miscall a afferent pupillary defect on the difficult ` swinging-flashlight ' test !  I have be care for patient with my Mini MagLite for more than 3 year . I would urge you to do the same !