The anodized red finish on the aluminum is a dead giveaway who makes these axle checkers.
They’re the originators of the axle checker for Mini 4WD, precision made by Kose Tools for Mr. Enomoto this set of axle checkers are only available in Japan. In order to drill this precisely they’re actually a 3 piece design, the aluminum is the outer sleeve and the inserts are brass.
Set includes 2 dimensions.
1.99 is for checking reinforced axles and 1.97 is for checking hollow axles. As with anything precision take care while using them.