A new stress reliever is small in size. That was one of the benefits of fidget spinners which caused their popularity. It is also multifunction: relieves stress, focuses the mind, entertains. There are several mastery levels: basic, advanced, expert.
A new hand spinner is a most recent toy for adults and children. No doubt it is gaining popularity literally every day. So, yes, a fidget roller Mokuru is a new hit and potentially top dropshipping product.