This is the MG Mass Production Type Hyaku Shiki Kai (with a catch). It's a Premium Bandai limited item, but this particular Hyaku Shiki Kai has a catch. I originally bought this kit because I wanted the Hyaku Shiki Ver. 2.0 without the chrome plating... Even with the included Kai parts, it's still cheaper than the chrome-plated general release version, making it a great kit for those who like to paint... But every time I see the completely unused new added parts, I feel a pang of regret... So, I decided to reuse them. I tried incorporating the Kai parts into the Ver. 1.0 as a test... and it seemed like it might work, so I immediately tried it out.

MG Hyaku Shiki ver1.0 Modified Mass Production Type Hyaku Shiki Kai | cozzy.knight's Gunpla works