A. H. Grebe & Co. 3-4 Get a print! $8.00 Add to Cart Product Information: Model:3-4 Manufacturer:A. H. Grebe & Co. Schematic Pages Page 1 Schematics Content Page 1: Electrical Test Chart Grebe Superhet. Model 3-4 Please note: we carry a wide range of products which will fulfill the specifications above. Please use our search function or browse our products to find what you need!