Low height chocking skid for left rail (as viewed from the handle end of the skid). 4-inches high at handle end and 17-1/2-inches long. Tamper-proof, light-weight skid for blocking one end of parked freight car. Rail skid uses friction from wheel pressure to hold car steady. For flush rail. Use on flat track. When using rail skid at one end of freight car, always chock other end of car with conventional steel wheel chock. Place skid in front of wheel, then roll wheel up onto skid. Apply car or locomotive brake after skid is under the wheel. Weight: 16 pounds. Product of Aldon® Company.