Shown below is a practice version (throwing dummy) that looks a lot like the Type 97.
It has a dummy fuze, made of solid steel, with two drilled holes for the safety.
I am unsure if this is a T97 version, and would like to know what other collector might think of it.

Unlike the type 97, this practice grenade has a rounded base, and is longer then the live grenade.

Total length : 110mm
Body length : 84mm
Diameter : 46mm
Weight : 385gram

Photos and data © Dr. Ruby.
normal Type 97 compared to this practice grenade :