There are dozens of different types of screwdrivers on the market. Generally, they’re classified by the type of drive tip that corresponds to a specific scre­whead. The three most common types for woodworkers and DIYers are slot (a.k.a. flat), Phillips (a.k.a. cross­head) and Robertson (a.k.a. square). There are also application-specific screwdrivers such as insulated (pre­ferred by electricians), torque (widely used by mechanics and machinists) and tri-point (used in the digital industry). Ratcheting screwdriv­ers rely on wrist power but use an internal ball-bearing mechanism that enables you to make multiple turns of the screw without removing the tip from the screw, saving time and reducing effort. The most impor­tant part of the screwdriver is the tip, which can be made of high-speed steel, stainless steel, tool grade steel, titanium or a blend of metals. Tips on low-cost screwdrivers tend to deform prematurely. Handles can be made of wood or plastic, and in a variety of shapes, sizes and configurations. Select a handle that best suits your hand size. Screwdriver sets can con­sist of a single type (e.g. Robertson) in a range of sizes or a range of screw­driver types in various sizes.