As there are various baseball theories in the world, baseball equipment manufacturers have a mission to continuously develop new baseball equipment.
"Swing the bat from top to bottom." "Swing it parallel to the ground with a level swing." "If it is parallel to the shoulder line, it's not an uppercut, so swing like you're scooping it up."
"Return the head at the moment you hit the ball!" "Don't turn your head back. Swing forward." "Lead with the pull hand. Hit the ball with the push hand!" etc.
Nowadays, there are baseball terms flying around that we had never even heard of a decade ago such as vertical swings and barrel zone.
There are so many different baseball theories, hitting theories, and pitching theories that could almost confuse our minds.
The Summer, 2021
I had a chance to talk to one of my coaches in high school. He told me about the interesting batting practice overseas.
It looks like you have separate grips for each hand and hit with both hands apart.
Oh, I think I have seen this batting practice before!!
I see. It it so different from when I was playing, but this kind of batting could become mainstream!
Would there be a demand for it, If we make this second grip as an external product.
Anyone can easily place it to their own bats. It could be a great idea! We should make a sample of it!
The Summer, 2021. After about a year of development
In recent years, Japanese professional baseball players have also been enlarging their bodies through training, improving their batting form, adopting the movements of MLB players, and obtaining a variety of information from social media and internet sites.
Even when it comes to batting, the players and instructors who come to Field Force indoor practice ballpark have a variety of hitting theories.
I believe that the instructors of baseball teams and clubs are gathering information on a daily basis, keeping their eyes open to see how they can provide practices that suit their players.
The baseball equipment manufacturers are the same.
Because of the variety of hitting theories, Field Force, which develops specialized products that are attentive to the needs of the players is able to provide the world with baseball equipment that enables various types of practice.
It starts with visualization with illustrating examples.
First, how the second grip should be attached to the bat?
In order to make a product that can actually be used for tee batting and toss batting, it must have a structure that is strong and stress-free in use.
From left to right
1. Initial sample focused on smart appearance : When it is used to hit the ball, It slips off right away.
2. Second generation sample with two top and bottom stops for stability : It gets in the way of the hand holding the bat.
3. Third generation sample that eliminated two problems : The U-shaped screw that attaches to the bat is too short for thick grips and comes off easily.
4. Final sample that was adopted : The product passed the strength test of 1,000 swings and is for commercialization.
Ms. Kobayashi of the Planning and Development Division and Ms. Tachibanada, the manager of the women's baseball team at Riseisha High School
Ms.Kobayashi of the Planning and Development Division knows Ms.Tachibanada well since she was an active player. Ms. Tachibanada contacted her and said, "There is this batting practice where players hold both grips separately and hit the ball.I think it would be interesting if Field Force commercialized this product".
After about a year of development, we were finally able to commercialize the product and begin sales.
In order to commercialize the product, we had male staff who used be fielders try the product and repeatedly discussed about "palm up", a recent trend in baseball.
As a baseball equipment manufacturer, Field Force has to always remember one thing.
It is "to be a true asset to the players"
Therefore, we need to deliver practice products that will be true assets to the players who practice batting with this palm-up theory.
Because there are so many different baseball theories out there,
Field Force, the baseball equipment manufacturer
has a mission to continue product development.
This product was named "Top Hand Grip", and just as the name implied, we have received reviews saying that they could master the use of the top hand (catcher side) and the opposite bottom hand (pitcher side). We had received influx of orders right after it went on sale. 
A key point is to tell what the wrong usage of the product would be.
This is not a product to practice returning your wrist.
You can check if your hands are parallel when you catch the ball and if one hand out of alignment with the other.
This product allows you to check how to launch the bat and catch the ball. Do not swing out with your wrists turned, but let the bat goes forward and swing out.
※There are many different theories of hitting, and we do not mean to deny other theories.
Be sure to install on the grip tape.
Because the product is tightened with screws, it may leave marks on the grip of the bat.
Remove when not in use.
If the screws are loose, it is dangerous because it may come off when swinging.
This product is for learning swinging movements. Do not swing excessively.
Our challenge to product development by the president and staff of the baseball equipment manufacturer who sincerely care about kids will continue without end.