"New"
The product may have been unpacked but is otherwise always complete with all accessories and labels. So you get a brand new product for a reduced price where it has only been unpacked.
"Very good"
In this case, the product has been unpacked and may be missing a label, the product has been used on a few occasions. The product is complete with all accessories.
"Good"
The product shows minor signs of use and may lack accessories.
"Okay"
These products may have clear signs of being used, may have cosmetic damage and may lack accessories.