The beam angle is the angle in which light is distributed. A typical recessed light bulb or light source will have a beam angle around 40°, conventional or integrated. The beam angle helps push the lumens (light output)down from the ceiling or light source to the intended surface. If you have a very tall ceiling height you may want to use a light with a narrower beam angle than 40°, but for most applications 40° or so will be adequate. PRO TIP: Beam angle plays a very large roll in the amount of perceived light on a surface. For example, two recessed lights both have a lumen output of 1000 lumens, one is 40° and one is 120°. Your counter-tops, cabinetry, furniture and flooring will appear much brighter with the 40° beam and will appear much dimmer with the 120° beam. This effect will be even more evident the higher the ceiling. The 120° beam creates this effect because the lumens (light output) are too widely distibuted. The light needs to be distributed in a narrow enough beam to push enough concentration of light down to the intended surface, such as a table, counter-top or floor space.