Seal Spray Foam High Performance Insulating Closed Cell Foam Spray Can Kit w/Gun Foam Applicator and 1 Can of Cleaner (300 Board FT-12 Cans) - Walmart.com
Open Cell vs Closed Cell Foam Insulation: Which is Better for My Home?
Spray Foam Insulation
Understanding R-Value for Commercial Spray Foam Insulation
Diminishing Returns of Closed Cell Foam. Depth, R values and Cost Savings? (info in OP comment) : r/buildingscience