Trying to perform my maximum reps on the gripper at the lightest weight!

So this video is showing me performing as many reps as I can on the gripper at the lightest weight. After 100, your forearm start paining slightly and then after 200 your forearm starts paining a lot but you can push till 300 reps after which it is close to impossible to get to 350 reps or 400. I performed 300 reps on the gripper.