I specialize in designing Electrical and electronics Product PCB.
My job is to design functional and tested product PCB for your application. Just tell me the requirements for your product: price, deadline and required features list.
You want some products to be developed. Great! I will design it. I will order a few sample PCBs, assemble and test them. After testing and debugging I will ship them to you, so you can verify my testing results. This costs a bit extra for you, but you are buying 100% working circuit design which needs no testing. Just take it and use it in your project.