Bold, clear, and complete stamp of an 'O Under a Roof' maker's mark. This is an undocumented mark.
This mark began showing up on eBay in 2015. I've got a couple of them and have seen a few more for sale since then. I assume they came from a newly discovered cache of floats with this great looking mark.
All examples of this mark have been stamped on 5 inch floats.
This float was purchased from an antique seller located in Oregon.