When the All Nations F3 Engine Kits were first released, grill work was simulated with a painted black rectilinear pattern on a clear or translucent plastic as inserts. Conductor Railway Hobbies is redefining the art of upgrading details for the Model Railroader. Given my roster of engines for the Chicago Great Western Railroad that includes F3 A & B units, 3D Printing has brought with it the opportunity to improve older models with finer details. The old translucent painted pattern never really looked all that good when mounted on the model however the idea was to be able to see the details behind the grills, actually you could not, but the idea was good. So in restoring old F3 units, 1 photo shows the before while a 2nd photo shows grill work on an unpainted F3 B unit body at a 30% infill at 0.50 thickness. For sale is 3D Printed mesh in the rectilinear pattern at 0.50mm thickness with a 0.20mm 1st layer. Available in either 30% or 40% infill sizes, either set will do a pair of F3 A & B units. The one photo shows the 30% on the left and the 40% on the right. 40% has slightly less transparency. The F3 B Unit requires 12 pieces of mesh and the F3 A Unit requires 10 pieces of mesh. For flexibility, special orders I can fullfill from your pick list or even print in different colors such as a rust brown color filament. For special orders, I will need a week to 10 days for delivery depending on when I can schedule your print job. Parts printed with PLA filament sold as is straight off the Prusa Printer built plate, all sales final no returns. PLA is not dishwasher safe and may deform in a hot automobile in the summer time as it has a relatively low glass-transition temperature. Made in the USA.