Bought to build bird feeders out of terracotta pots. They worked very well. It took me a while to master the technique but they persevered. One of the bites would have cost me about $40 at Lowes when I priced it, but I got a set of five for $8.
Pros
Diamond drill bit sizes: diamond drill bit set includes 5 diameters 3/8, 1/2, 5/8, 3/4, 1 inch, 5 cm and 5.5 cm length, good diamond drill quality tool kit