You get a lot of pieces for the money and on close examination, they all seem fairly well made. Additionally, the plastic case is better quality than I've seen with many other sets. Some people might lament the lack of any instructions. With 30 different tools, it would be useful to know what each one is supposed to do. I guess the manufacturer assumes that its customers know what they are doing.
With regard to compatibility, I use a Proxxon fine drill/grinder FBS 240/E
c/w its excellent keyless chuck. I use it for primarily for repairing and restoring old watches and for renovating small model steam engines. The 3.175 mm (nominal) diameter shanks of these tools fit my Proxxon perfectly.
All things considered, at under a fiver, this set is a very useful and well-priced addition to my toolkit. At this price, I might even buy a spare set to replace any bits that I may loose, break or wear-out.Toolzone 30Pc Deburring And Engraving Set