The reflector is one of the most important parts of your indoor grow light system.  You want to try to have even light distribution over your garden so choose the shape and size based on  your indoor garden parameters.  

   Air-cooled grow light reflectors are the preferred choice for most indoor growers because this gives you the option to vent the hot air from the grow lights separately from your grow room ventilation system allowing you to control your grow room environment more accurately.

Featuring Made in the USA Grow Light Reflectors from Sunlight Supply.