This is a 16 x 22 x 13" Photoflex MultiDome Q39 Softbox (Small). Photoflex makes a wide variety of softboxes for use on your strobes or hotlights. LiteDomes and MultiDomes are for use with strobes only. SilverDomes and HalfDomes may also be used with hotlights. All Photoflex softboxes require a speed ring adapter, which must be purchased separately.
Choose a softbox according to the size of your subject. For example, a small or extra small is appropriate for a head-and-shoulders portrait, or a very small still-life such as a paperweight. A medium softbox is good for a half-length portrait of an adult. A large is suitable for a group portrait of 3 or 4 people.
Choose a softbox interior color for the lighting effect you want. White is the most universal, giving the most softening effect. Silver gives a little more punch and crispness. Gold (with the MultiDome only) adds that punch, with a warmer tone.