①. Compatibility: 1/87 HO Model Train Test Track Module is designed to work with roller test stands. It is suitable for 1/87 HO scale train models of most brands. ②. Function: Test Track Bearing (roller trolleys) allows testing of model trains on the track or layout tracks. ③. Diagnostic Module: Single unit treadmill track is used for testing and repairing 1:87 HO scale trains. It can analyze idling performance and movement to identify faults (Note: Train Not Included). ④. Expandable: Multiple units can be connected for diagnostic setups. The reliable base helps ensure structural accuracy for exhibitions or repairs. ⑤. Including: 1 Diagnostic Treadmill Unit. ⑥. Specification: Material: metal and plastic. ⑦. Size Chart: 5.12cm/2.02inch. ⑧. Package Includes: 1/87 HO Model Train Test Track Module. ⑨. Note: Please allow slight errors of 1-2cm/0.39-0.79inch due to manual measurement.