A gravity knife is a knife with a blade contained in its handle, and that opens its blade by the force of gravity.

The main purpose of this opening method is that it allows opening and closing to be done one handed, in situations where the other hand is occupied. Hence, historically they have been issued to parachutists to cut off caught lines, such as lines tangled in trees, a major potential use of the gravity knife.

This wonderful gravity knife has been totally handcrafted and features Damascus blade and elegant slabs.  

90 mm long when folded and 160 mm long when fully opened

Razor sharp Damascus blade measures 65 mm long and is operated by a spring loaded thumb button to release the blade from both the open and the closed positions. Holding the knife with the open end down and pressing the button allows the blade to drop out, into position. Taking pressure off the button locks it there. To retract the blade hold the knife blade up and depress the button. The blade slides back within the handles.

Stainless steel back spring encased in a nickel silver frame with file worked thumb button. 

Nickel silver guard. The blade lock properly when opened with no wobble demonstrating a great technical skill in the construction of the knife.