Tea infusers should, in our opinion, be so designed as to have plenty of room for the tea leaves and infusion material to bloom for maximum surface area exposure. We quite like these deep stainless steel infusers which sit all the way down in a deep mug, and submerge into a small teapot, standard steel thermos and other brewing vessels making for an excellent infusion and brew. Super fine holes make them perfect too for fine plant material.