These develop dexterity, problem-solving and reasoning skills, hand/eye color coordination, shape and size identification, and more with these big, bright multicolored WOODEN JIG-SAW PUZZLES. The pieces are light in weight large in size ( about 3/4" thick for easy handling ), and interlock loosely so even preschoolers can assemble them easily. All are safe, sturdy, and water-resistant. Colored finishes are non-toxic and safe in the mouth. All of the puzzles can be used as hot plates and coasters as well. The designs lend themselves to be used throughout the house by all ages.