R-shape and BR-shaped incandescent reflector light bulbs have a built-in reflecting surface that generates a flood or spot beam spread. R shapes have largely been replaced by the more efficient "bulged reflector" or BR shape. The number after R or BR indicates the diameter of the bulb face in 1/8 of an inch increments.
Incandescent reflector bulbs differ from halogen PAR (parabolic reflectors) by the fact that the beam is a diffuse flood without the optical control available in PAR bulbs. BR bulbs are used primarily in recessed downlights found in residences, hotels, offices and food service applications.