Based on a 1950's-era tractor which was recreated as a cast metal toy in the early days of the LEGO company.
Sets are individually numbered out of 80 with sets 1-35 reserved for Inside Tour attendees and the remainder distributed to LEGO personnel involved with that particular tour. The numbering system is reused for each Inside Tour. The reverse of each tour's packaging includes a photo of that tour's attendees. Based on there being five tours in 2018, this set is limited to a total of 400 sets (80 in each packaging sleeve).