Do you mean credit card close style (Ironmind) or deep set style (Mash Monsters) for that certification style?
Rules for Closing a No. 2, No. 3, No. 3.5, or No. 4
Captains of Crush Gripper
1. The gripper must be an authentic IronMind Enterprises, Inc. Captains of Crush® Gripper
2. The gripper cannot have been modified or tampered with in any way.
3. Chalk (magnesium carbonate) may be used on the gripping hand, but rosin, tacky, etc. are specifically disallowed.
4. The free hand may be used to position the gripper in the gripping hand, but the starting position can be no narrower than the width of a credit/ATM card, and the gripster must show the official that he has an acceptable starting position by using his non-gripping hand to slide the end of a credit/ATM card in between the ends of the handles. Once this is done, the official will give the signal to remove the card and begin the attempt. Any contact between the non-gripping hand and the gripper as the card is being removed will invalidate the attempt, and the non-gripping hand must stay at least a foot from the gripping hand at all times during the squeeze. Similarly, nothing may be in contact with the gripping hand or the gripping arm from the elbow down (for example, the free hand is not allowed to steady the wrist of the gripping hand or hold the spring, etc.). The entire squeeze must be clearly visible to the official: the gripper cannot be closed while blocked from view and then turned and presented as already closed.
5. The gripper must be held with the spring facing up.
6. The handles must touch completely.