1-1/2" deep, 3-1/2" blank octagon boxes are used when installing ceiling or wall lighting fixtures but have no holes or knockouts, allowing you to add only the knockouts you need. Let Garvin Industries manufacture a custom solution for you! These octagon boxes can also be used as an outlet box for a surface conduit or convenience outlet. Garvin Industries’ octagon boxes are made with a versatile combination head 8-32 screw. These octagon boxes allow economical box installation when minimum wire capacity is required.