BoldDrop Stainless Steel Fine Filtering Loose Leaf Tea Infuser Basket for Cups and Mugs Designed for in-cup use for mugs and cups. Fits most standard sizes. Includes versatile cover that also functions as a drip tray. Microscopic 0.4mm hole size allows for easy water flow, while preventing debris transfer. Compatible for brewing all types and strengths of tea. High quality food grade (304) stainless steel