This one prong Root Hook from Kaneshin is made of stainless steel and is one piece. This is easy to hold in your hand and is lighter than the wood handled root hooks. The No. 552 is shorter than the No. 553.
Root Hooks help speed up the repotting process as it helps to remove the soil that is in the roots along with aiding the root detangling process. With this being all one piece you do not have to worry about the wood rotting or the steel separating from the wood and becoming loose.
For basic usage and tips on how to care for your bonsai tools please visit this link. Bonsai Tools & How to Care for Them