Real IMR's?

I got an order today from bestinone of IMR's in 18650, 14500, and 10440. I've never had any IMR's before so I'm wondering how I can test them to see if they are really IMR's. My first observation is they seem lighter weight than LiCo cells. Also they are flat on top instead of with a button. They are generic and have IMR stencilled on the side, but I'm thinking that isn't hard to do. I think the highest draw the Turnigy hobby charger will do is 1A, but I will check on that later.

Simplest test is output. If you have two lights of the same performance, put an IMR in one and a normal rechargeable in the other. The lower internal resistance will show the difference in output.

Especially from lights that like a lot of current.

I'll try the Manafont XM-L drop-in which I'm thinking is direct drive anyway. Well, maybe the KD drop-in because I don't want to kill the Manafont one.

Best to have two of them so you can compare side by side.Then you'll pick up quite small variations.

Or use a meter.