Stress Squares are larger than biodots (1/2" by 1/2"). Each square of temperature sensitive material has strong adhesive backing. The squares CHANGE COLORS as temperature changes. Use adhesive back to stick the Stress Square to tense areas. Inexpensive and unbreakable, 10 degree range from 81 F to 91 F. These have a glue or an adhesive back. Simply peel them off. You can stick them on skin, letterhead, business card, student ID, or any promotional or advertising item. Instruction cards are available for 10 cents each. You may also purchase Stress Square Card set which has a quantity of 36 squares and includes the instruction card.