This is the full kit, with three different scales to choose from ranging 14 foot models all the way up to 86 feet to really show your kids how scale affects a model. Choose one or assign different groups all three. Recommended pre and post activities that really spark curiosity, draw out understandings, and lead to excellent conversations to post on your Driving Questions Board. The entire activity can be completed in 40-60 minutes, all you need it toilet paper and an hour. This activity is recommended for grades 5-8.