– You can buy the digital album from:
Since you're looking for a "best box" version, I'll assume you might be referring to a high-quality audio file or a special edition release. Here are a few options:
The set includes a jacket frame pin badge set featuring designs from past TV theme song covers and a special booklet. Official Purchase & Streaming Options
This limited-edition box set serves as the definitive audio archive for Kamen Rider fans, organized into thematic discs: TV Theme Song Best (Discs 1–5):
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