| Supplier legitimacy | A legally registered business with a verifiable manufacturing or trading address and an established export process. | Business registration details, factory or warehouse video, trade references, export documents, and a video inspection. | 15% | Verify directly |
| Brush compatibility | The brush should be suitable for photovoltaic glass and compatible with the module frame, surface coating, pole system, and cleaning method. | Technical drawing, bristle material specification, shaft dimensions, compatibility statement, and sample testing on the target module type. | 15% | Sample required |
| Surface protection | Soft, non-abrasive bristles that do not leave visible scratches, residue, or metallic contact marks when used according to instructions. | Controlled before-and-after inspection, magnified surface checks, repeated-use testing, and written cleaning instructions. | 20% | Critical criterion |
| Cleaning performance | Effective removal of common dust, pollen, bird droppings, and light soiling without excessive water, pressure, or repeated passes. | Standardized field trial using the same panel area, soil condition, water volume, operator method, and before-and-after photographs. | 15% | Compare samples |
| Material durability | Bristles, joints, fasteners, and handles should resist water exposure, normal cleaning chemicals, UV exposure, and repeated mechanical use. | Material declarations, accelerated-use records, corrosion checks, replacement-part availability, and warranty terms. | 10% | Check documentation |
| Quality management | Documented incoming inspection, production checks, final inspection, defect handling, and traceability procedures. | Quality manual, inspection checklist, sample inspection report, corrective-action records, and applicable ISO 9001 certificate verification. | 10% | Audit recommended |
| Customization capability | Ability to customize dimensions, bristle density, pole connection, packaging, labels, and operating instructions without compromising safety. | Prototype drawings, sample approval process, tooling charges, minimum order quantity, and change-control procedure. | 5% | Review project fit |
| Packaging and logistics | Packaging should prevent deformation and moisture damage and clearly identify quantities, handling information, and shipment contents. | Packaging specification, carton measurements, loading photographs, Incoterms quotation, lead time, and pre-shipment inspection plan. | 5% | Confirm per order |
| Commercial terms | Transparent pricing with clearly defined sample fees, tooling costs, payment terms, lead time, warranty coverage, and after-sales responsibilities. | Formal quotation, proforma invoice, warranty policy, service-response commitment, and written dispute-resolution terms. | 5% | Compare total cost |