I use Calumet because if they say they have an item on stock they have it on stock. Delivery is nearly always next day. The items I buy are always in perfect working order (accurate focusing,perfect exposure, no slow draining batteries) unlike items I have bought from overseas. Calumet also had the lowest price in the UK by £200 on Nikon D5 CF version. I just want to take photos with a camera that does the job perfectly so I can get on with my photography hassel free. I have had 3 Nikon lenses and 2 cameras over the last 5 yrs all still working perfect. I know I am getting the genuine item from Calumet .Beware if you go elsewhere I learnt the hard way.