This apparatus is made of aluminum wire, three sixteenths of an inch in diameter, according to measurements of the infant's arms. The apparatus shown in the accompanying figure measures 5½ inches in its longest measurements. The three rings are 1¾ 1⅞ and 2½ inches, respectively, in diameter. It is bent at a slight degree to conform to the infant's arm. It has the advantages over the common paper cuff in that it is light, cool, more durable and easily sterilized. It is inexpensive and can be easily made in a short while. I am submitting it on account of its simplicity, comfort and efficiency.
ANDERSON WW. THUMB SUCKING APPARATUS. Am J Dis Child. 1930;39(1):70. doi:10.1001/archpedi.1930.01930130082008