Integral FRN clip
The integral FRN clip is a clip that primarily exist on older Spyderco knives and very small knives like the C28 Dragonfly This clip is molded on the back scale as a piece of that and is an integrated part of the knife. On older knives this is a thin clip (The red and green C10 Endura In the picture below) and on the next generation it is slightly thicker. The thicker clip came when Spyderco received complaints that the integral clip was prone to breaking off when catching on things.
Other variations of Integral FRN Clips: