Coco Ring Flash Adapter for Nikon SB-900 Flash with D300, D200, D70, D80, D50, D40, D40x, D60, & D90 Digital SLR Camera’s Price: $29.99 (as of 29/06/2019 12:52 PST- Details)

Minimal light loss from the flash’s standard output
Doesn’t affect flash’s color temperature
Requires no modifications to flash unit

Usually ships in 2-3 business days