In the United Kingdom pocket knives carried in public can not have blades that lock open. Spyderco addressed this by developing a non-locking folder called the UK Pen knife. The blade is held open by a notched-joint at the knife’s pivot, similar to traditional slip-joint penknives. To achieve a heightened sense of control and comfort, Spyderco designers added a deep finger choil positioning the index finger directly under the thumb. The factory model number for the UK Pen is Spyderco C94.