These bisque moulds have been handmade by Clae. 
Slump moulds are a good way to reproduce a specific size or shape when you are hand-building bowls or cups. 
Bisque moulds are lighter and sturdier than plaster moulds, and are much easier to clean.
 
Clae Bisque moulds come in 5 sizes:
 
01  12cm in diameter and 8.5cm tall
02  13cm in diameter and 8.5cm tall
03  15cm in diameter and 9cm tall
04  17cm in diameter and 9cm tall
05  23cm in diameter and 12cm tall
 
Note that because these moulds are made by hand there is some variation in measurements between each mould.