Working for a product company: what skills a tester needs

I've been working in a product company for many years and have conducted hundreds of interviews with outsource and product testers. And now I want to share my observations about what differentiates testers in these two areas. To do so, I will walk through the main stages of product development and reveal the competencies that are required at each of them. 

 The talk is useful for those who intend to immerse themselves in product testing.