This was obtained at an auction of a secret collection. The details are uncertain, but it is likely X from a soft vinyl figure set of the 7 Riders. However, the type with the back painted red is rarely seen, so I think it's quite rare. The condition is also quite good for its age. The muffler's originality is unknown, but judging from the material and wear, it's likely original (this is just my personal opinion). Please ask any other questions in the comments.