calculating Vreff for a4988 that comes with kuman kit

I got the Kuman ramps kit on amazon awhile ago. It has the a4988 drivers (I know that the drv8825 are better and I will upgrade at some point).

now that my machine is working and cutting, I want to tune these things. On the wiki, it says that I need to know the resistance of the sensing resistors. It also says that while the polo drivers are .05 ohms, that chinese clones are usually much higher requiring much more voltage.

I assume that I have a Chinese clone. but is there a way to verify the exact resistance of my drivers?

I figured it out. the resistors say r100 on it so it is a 1ohm resistor. 1.2v is 1.5a. I do not think that I really want to go much higher on this stepper driver.