This glass tea infuser is made of food grade, lead-free borosilicate glass that can withstand high temperature up to 150C.   Easy to use: 1. Fill 1-2 teaspoon of loose leaf tea into the infuser2. Place infuser into you tea cup 3. Pour water into your cup the water will automatically enter through the incisions at the bottom of the tube. 4. Steep to your desired time, stir and remove to place into the glass holder.