Based on your request, you didn't provide any business context, target, or closing typical characteristic of their customers. So, any specific filter for a customer search will require that information. Without that information, a random example of a LinkedIn Sales Navigator search could be:

```json
{
  "industry": "Financial Services",
  "job_title": ["Investment Advisor", "Financial Advisor", "CFA"],
  "location": "San Francisco Bay Area",
  "business_size": "1000+",
  "seniority_level": "Director"
}
```
Let me know if you need help with another context situation or with different filters.