ROCKWOOL® R-15 stone wool insulation delivers outstanding thermal performance, fire resistance, and sound control in one durable insulation solution. Designed for 2x4 wall assemblies, these high-density batts fit securely between standard stud spacing while maintaining their shape over time. Made from moisture-resistant stone wool, this insulation is ideal for residential and light commercial projects where comfort, energy efficiency, and long-term durability matter most.