The 3-in-1 Snap Ring Pliers have swappable heads to provide different angles of approach when removing and installing snap rings. Additionally, you can choose to install the heads on two different sets of pins. One set will make the jaws open when the plier handles are squeezed, most commonly used for external snap rings. The other set of pins will make the jaws close when the plier handles are squeezed, most commonly used for internal snap rings. The included heads consist of two straight heads, one 45 degree head and one 90 degree head.