Confirmed Fitment
Glock 21 Magazine Loader
The Glock 21 is confirmed to fit the Super Thumb ST2 magazine loader from ADCO. The original Super Thumb loads Glock 21 magazines faster and with far less thumb strain — a purpose-built tool, not a one-size-fits-all compromise.
Your Fit
Super Thumb ST2
Wide Body Double-Stack
Width
1.5" (38.6 mm)
Height
1.01" (25.4 mm)
Not 100% sure? Confirm before you order.
Super Thumb loaders are model-specific. Use the Model Finder to double-check your exact firearm and magazine, or call ADCO Arms and we'll confirm the right loader for your Glock 21. Every Super Thumb is backed by a lifetime warranty.