Westcott has also released the Rapid Box XL (£300; $300) and Rapid Box XXL (£360; $360), both large octagonal softboxes with an umbrella-folding design. But these fit directly to the bayonet mount of a studio flash head (or Skylux LED) rather than the Phottix/Apollo format, which has the light inside the softbox facing backwards.
The Rapid Box XL is 36 inches (91cm) in diameter and the XXL is 48 (122cm). Each is available with a choice of Bowens, Balcar or Profoto speedring. A £35 deflector plate is available separately.
Phottix products are sold directly from their online store, as well as distributed internationally. Westcott products are available in the UK from authorised JP Distribution dealers and in the USA from Adorama, B&H and others.