Vices perform several vital functions, from simply holding a item securely to exerting pressure or even acting as an anvil during hammering operations. Various different types are available, some allowing for the vice jaws to be positioned in any orientation. Some may be permanent fixtures and others may be easily removable, simply clamping to a table top. On a smaller scale, PCB holders allow for the board to be safely held in place at a convenient angle. Assembly work often requires pieces to be temporarily clamped together, such as when waiting for adhesives to cure, and this can be achieved using small, spring-loaded clamps or larger, adjustable clamps of various sizes. Some processes, especially disassembly, involve the use of pullers. Different types perform different functions and the most familiar are the two or three-legged 'bearing puller' types, which can operate in internal or external mode. These are not used exclusively for bearings and some miniature versions are even suitable for stripping binding posts. Others can dismantle bearing races. Other types of separators may be needed to free some stubborn components, and specialised pullers are usually needed for armatures. Pullers may also be used for bushes and sealing rings. Assembly is usually easier and suitable fitting kits are available.