Sigma EF-610 DG ST Super Shoe Mount Flash for Nikon. No working issues. Used a handful of times. Can be used in the hotshoe or off camera.
"NA-iTTL Nikon
ELECTRONIC FLASH EF-610 DG SUPER
It is compatible with new i-TTL system. Availability of TTL Auto depends on the lens, but this system can be used with all Nikon camera models. It is possible to use Manual Flash as well as distance-priority manual flash, which is peculiar to Nikon (except D1X and D1H cameras).Wireless Flash function can be used with F6, D90, D80, D70, D70s, D60, D50, D40, D40x, D200, D300, D2 Series, D3 and D3X cameras. Red-eye reduction control, Rear-Curtain Synchro and Exposure Compensation functions are also available (except some camera models). Manual switching of the amount of light is from 1/1 to 1/64. Auto-Power Off function shuts off the power if the flashgun is not used for 80seconds." This information regarding the flash was pulled from the Sigma site in the link below.
https://www.sigmaphoto.com/flashes/flashes-resources/ef-610-dg-super-flash