Sales-qualified leads are leads that have been vetted by both marketing and sales teams and have expressed a clear interest in buying. They have gone through the stages of lead generation, lead nurturing, and lead qualification, and have met the criteria for being ready to buy. Sales-qualified leads should be given the highest priority, as they are the most likely to convert into customers and generate revenue. Reference:
Cert Prep: Salesforce Certified Sales Representative, unit "Sales Strategy and Planning".
The Ultimate Guide to Lead Prioritization, section "Focus on inbound leads".