The plastic knife has the same blade that is used in the Original Ring knife.
This line of plastic ring knives was developed in 2009 as a safety knife. The polycarbonate band is made with a 'rib' in the back that can be cut (with another Handy ring knife). Cutting this rib allows the band to accomodate different sizes of fingers and also allows the user to pull out in the event that the blade would get caught in machinery etc. Sold and priced by the dozen