Resource Hub An employee of Tech-Tool Plastics, an HAI Manufacturer and Supplier Member based in Fort Worth, Texas, USA, inspects a Bell OH-58A/C aft door wedge window. This replacement window for a Bell OH-58A/C helicopter is among the hundreds of stock and custom models manufactured at Tech‑Tool Plastics. The windows are made by hand at the family-owned business and undergo multiple inspections during the manufacturing process. Founded in 1976, Tech‑Tool Plastics is the only company that exclusively makes replacement helicopter windows.