Magazine loader by RAE Industries.
This is the classic RAE-701 designed to fit the widest range of magazines in a single loader.
The RAE-701 is a "one size fits most" design.
Double Stack Mags:
Mags that are considered "standard width" meaning up to 7/8" wide or 22.5mm or .885"
Popular models for this loader include Sig P365, Tauraus PT111 and many more.
Popular Glock Mags will need RAE-730 which has a slightly wider profile (click here)
The internal profile guides single stack magazines from 3/8" in width up to 5/8" in width. A popular choice as well as double stack magazines