Knob and peg puzzles make the placing and removal of puzzle pieces easier. Because, in small children, fine motor skills are not honed, using a pincher grip (thumb/finger) can be quite difficult. The large pegs or knobs provide a sturdy base which is easily grasped. Most knob/peg puzzles are wooden therefore sturdy enough for more rugged use. Playcentres, preschools and kindergartens often choose these style of puzzles because of the ease of handling. Playing with puzzles requires trial and error processes which involves hand-eye coordination.