KATO HO SCALE HV3 ADD ON SET (FOR USE WITH HM1 AND HV1)... PRODUCT INFORMATION: Variation (V) sets are designed to integrate with the Master sets or existing UNITRACK layouts to provide a means for simple track expansions such as passing sidings, parallel ovals, and crossovers. These boxed track sets will be sold in Japanese style packaging. Interchange Track Set with #4 Electric Turnouts/Switches.