1. This is A-Grade Cross Pick which is different with most cross picks on the market. It's four direction blades are made of high flexibility strong carbon steel blade different with steel wire(easy to break). 2. It can insert into cross cylinder to open very smoothly. 3. This klom A-Grade Cross Pick, It can open not only cross invisible door lock, cross dead bolt door lock, but also small size cross padlock, cross steering wheel lock, cross bicycle lock, small size cross cylinder... and so on. 4. There is signal on the black round turning bolt which is special designed to help locksmith to aim the center position while opening cross lock. 5. It is very easy to change and install tension wrench by a small screw driver on the side of black round turning bolt.