I bought a classic T - 40. I think that L type is the best for narrow place and strong tightening. It is cheap among many kinds of handling with Monotaro san. I thought that it is essential because it may be troublesome if it does not correspond to the screw with the antidote stopper in the future. This product is compatible with screws with tamper resistant only for the long side, I think that it is enough for the shorter one, but it is enough. I think that I can use something in the future.
There are products that can not be sold without this tool. There are few customers who have this type of wrench, so there are not any people who buy it with one time use, so it is in a state of selling. It is saved if there is cheapness like the Allen key wrench.