1" x 1", Clear, Dual Lock Re-closable Fastener, Hundreds Of Mushroom Shaped Stems Interlock When The 2 Sides Are Pressed Together, Snap Announces That The Fastener Is Engaged, Apply At Temperatures Above 50 Degrees Fahrenheit, 10 Degrees Celsius, Make Sure Surfaces Are Clean & Dry, Do Not Use On Car Mufflers, Furnace Exhaust Tubes, Or Anywhere Temperature Exceeds 300 Degrees Fahrenheit, 149 Degrees Celsius.