This　article　describes　the　design　of　a　versatile　Vehicle-to-Everything　(V2X)　On-Board-Unit　(OBU)　with　a　modular　implementation　and　wide　range　of　wireless　and　physical　interfaces,　for　use　in　real-world　V2X　experiments.　The　basics　of　V2X　communication　is　introduced,　as　well　as　the　design　requirements,　component　selection,　form　factor　consideration,　and　prototype　iterations.　This　article　concludes　with　the　result　from　several　real-world　outdoor　trials　in　the　UK.　The　result　indicates　that　the　hardware　is　fully　functional　and　able　to　perform　to　the　intended　specification.　Further　areas　of　improvement　are　also　discussed.　©　35th　International　Technical　Meeting　of　the　Satellite　Division　of　the　Institute　of　Navigation,　ION　GNSS+　2022.　All　rights　reserved.