On Fri, 14 Apr 2017 07:03:05 -0700 (PDT), True North wrote:

Spyder knives have been around for a long time. They have a Loop on the upper side of the blade for one handed operation.
I was looking at one about 20 years ago but they were too expensive up here...maybe double the posted price of yours.

I've had one with a big loop for the thumb to open it. These are just much, much easier to open.