Round Soffit Ventilation -White Meets Building Regulations at 250mm centres for roof pitches over 15 degrees Size: 76mm Spigot (3") (Inner Diameter) Free Area cm²: 25 Fit before or after installation of soffit boards. Specifically to prohibit entrance of large insects. BS 5250 Section 6. Use 76mm dia. hole saw / cutter (BM403) For Brown see K-BM406-B
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