China Sourcing Agent — Find Exact Aluminum Profile Supplier for LED Panel Lights

I am setting up a factory to manufacture LED backlit panel lights, and I need help finding a specific aluminum profile supplier in China. WHAT I NEED: I am looking for an aluminum profile that is specifically used by companies manufacturing LED backlit panel lights — not a general purpose aluminum profile, and not a window or door profile. Specifically the type used as the outer frame for LED backlit panel lights. I do not have CAD drawings or technical specifications. I only have reference photos of the profile, taken from a disassembled panel. I am also not sure about the exact aluminum alloy type, so please do not assume or guess this. The supplier or factory should confirm it. I also need a matching corner connector piece that fits inside the profile ends to join two pieces at ninety degrees, without welding. A reference photo will be shared after hiring. The profile must be finished in white powder coating, ready to use. ORDER QUANTITY: This would start as a trial order of around five hundred kilograms. If the profile proves suitable after testing, future orders will be much larger on an ongoing monthly basis. YOUR TASK: Use whatever method works best for you, whether online platforms, your professional network, or factory visits, to identify this exact profile type and find at least three different factories or suppliers that offer it. The match needs to be based on actual use and application in LED panel light manufacturing, not just visual similarity to a general profile. For each supplier found, please gather: their product photos, technical specifications confirmed by the factory such as alloy type and wall thickness, pricing per kilogram, their minimum order quantity, whether they also provide the matching corner connector piece, and whether they have previous experience supplying this type of profile to lighting manufacturers. VERIFICATION: This is very important. For each supplier, I need some form of proof that they are a real, genuine manufacturing factory, not simply a trading company. This could be a short video of their actual production line and stock, photos taken on site if visited in person showing the factory environment, or some other form of verification showing the real facility. Product photos alone, without any factory context, will not be considered sufficient. DELIVERABLE: A simple written report summarizing the three or more suppliers, including their photos, verification proof, specifications, and prices. BUDGET AND PAYMENT: This is a fixed price task. Payment will be released only after at least three verified suppliers are delivered, matching the exact application described above, accepting the trial order quantity, with valid proof that each is a genuine factory. A profile that only looks visually similar but is not confirmed to be actually used for this specific application will not be accepted as fulfilling the task. This is meant as a starting task. If it goes well, I would be interested in a longer term sourcing relationship for much larger future orders. WHO I AM LOOKING FOR: Someone experienced in sourcing physical products from Chinese factories, comfortable communicating with manufacturers in Mandarin, ideally based in China. Examples of similar past sourcing work, especially with proof of genuine factory verification, would be a plus. Reference photos of the profile and the corner piece will be shared once a freelancer is hired for this task.