LINEAR SLOT DIFFUSERS

I think this one is Standard independent, besides small dimension Slot dimensions are defined by a Structural Code

The standard metric bolt diameters are specified in the standard ISO 898-1 Tables 4 and 5 For typical coarse pitch thread bolts the standard sizes are: M3

standard slot sizes Standard drop-in T-nuts can be loaded from the side or end of a T-slot profile, making it an ideal fastener for 8020 builds with hard-to-access ends

standard parking slot size It also specifies allowable hole sizes and types for bolts, including standard Nominal Hole Dimensions, in Hole Dimensions Bolt Standard Oversize Short-Slot