SB910 SB-900 Flash Softbox Bounce Diffuser Cap Box for Nikon SB-910/SB900 Flash | eBay
Amazon.com : PhotoTrust 8"×8" (20cmX20cm) Universal Collapsible Round Studio Softbox Flash Diffuser for On Camera or Off Camera Flash Gun Compatible with Nikon SB-500 SB-600 SB-700 SB-800 SB-900 SB-910 Canon Speed :
opteka sb-1 mini universal studio soft box flash diffuser for the nikon sb-900 sb-800 sb-700 sb-600 sb-400 sb-700 sb-900 sb-910 flash units - Walmart.com