The term SSKI stands for saturated solution potassium iodide.
Saturated solution means exactly that, the point at which no more KI will dissolve into the water as evidenced by a small amount of KI remaining undissolved at the bottom of the container. Mixing a large batch requires no measuring as KI is added until no more will dissolve and some solids remain on the bottom. The liquid poured off this container is then true SSKI . Anything sold as SSKI that will still hold more KI is watered down and dishonest as I'm sure the ebay variety is. You get what you pay for, better to deal with someone you know and trust.