Nite Ize. believes no product is too small or basic to be improved.
The classic utility carabiner. 
Innovative slide-to-lock feature that securely locks the gate with a simple push and slide movement. and unlocks when you want it to just as easily.
A cross sectioned. rectangular stainless steel body that's durable. low profile. and slim; it feeds more easily through smaller openings and rests flat
in pockets.
Available in sizes:
#6 (to tackle the largest items).
#4 (perfect for attaching to a belt loop or
backpack to carry larger items).
#3. and #2 (for carrying smaller items like keys. and attaching to zipper pulls).