Selkirk 187704 Wall Thimble, 4

Highlights:

• Size: 4
• #4RV-WT
• Type B vent
• Adjusts from 4-1/8 to 7L
• Wall thimble also serves as a firestop
• Used to ensure clearance to combustibles is maintained
• For approved gas appliances
• Use in single and multi-story buildings in accordance with NFPA 54 & 211