Superior detail in these do it yourself (DIY) models begin as a 4 inch steel sheet and when completed create a fabulous 3D miniature model. Easy to follow printed instructions included in every package. Build your entire collection today! The hop-on, hop-off New York City tour bus has become an iconic image around the city. Similar tour buses have become popular in many large cities as a fun and efficient way to see the sites. Difficulty: Moderate - 3 Sheets.