Those gaiwans are made by a creative and accomplished team called Bian(check here for more about Bian) in Jingdezhen.
Those gaiwans are made by rough clay , giving bumpy touch across the gaiwan. It is applied with silver or gold glaze outside the body and black brushed in swirls on the inside ,giving an aesthetically beautiful appearance.
Each gaiwan holds 130ml of liquid roughly featuring thick and strong body which helps to retain the heat well and prevents it from being broken easily. As the rim is extended fairly wide, the gaiwan definitely can prevent the hands from heat. In that case, we highly recommend to a new tea drinker starting to use gaiwan. The inside is glazed same with the exterior, making all teas available for brewing in this gaiwan.
See more details of the cups in the photos, check here.