Even though in CA you cannot conceal carry a fixed blade, I was still intrigued by ring daggers like the SOCP dagger. CS of course makes the Shanghai Shadow and Shanghai Warrior, but those are in a completely different league. There is also the Battle Ring and the Drop-Forged ring dagger, but I gravitated towards the utilitarian hunting models: the Bird and Trout and Bird and Game.
The B&T is the smaller of the two, with a 2-1/4" cutting edge. I went with the B&T because I wasn't sure if this design works well with the larger blade. In a pinch, I bet you could use it exactly like the ring daggers designed as a last ditch CQC weapon to create space between your attacker.
In practice, I just use the B&T as a utility knife around the house. It is my go-to cardboard breakdown knife. The small, thin blade cuts with minimal effort, and is big enough for most jobs. It also weighs next to nothing and fits inside any pocket. If I could EDC it, I totally would. This is another winner from Cold Steel.