Welcome to Defender Canada! 
T-H Marine Floor Drain and Vent Item # 985347
Description
Features:
- Works on fiberglass or carpeted surfaces
- Great for deck drainage
- Mounts as an attractive vent for compartments and pontoon furniture
- Color: Black
FD-2 Specifications:
- 4 1/4" overall diameter
- Mounts with 4 screws in a 2 1/2" diameter hole
FD-4 Specifications:
- 5 5/8" overall diameter
- Mounts with 4 screws in a 4" diameter hole