This is a tool (wrench) for the rear endcap of a CGS Hydra. I was never able to grip the rear endcap when the Hydra was installed. If I tried to unscrew the Hydra, I always ended up unscrewing the tube and leaving the rear endcap (which I could only grip and remove once the tube was removed). This is a simple tool to grip the rear endcap. It is made as two parts because if it was a full circular wrench, you couldn't fit it over the tube. Each side engages 3 lugs of the endcap (for a total of 6 of 8 engaged by the full tool). I printed it solid, and it is plenty strong. Obviously, you shouldn't use it when the Hydra is hot.
I created this is Sketchup and have uploaded the file.
The author marked this model as their own original creation.