I ask my fiber guy to send me a small sample of an 12-fiber Single-mode OS2 underground direct burial . I’m thinking perhaps a 6 or 8 inch piece. This arrives by freight. Elmers Glue for size comparison.

On the plus side, I like it and I think it will work going from the house to the gate (plus the gate is the access to the street, so if I can wrangle a real fiber connection from Skyline I’m set.) I’ll need around 400m or so to get there.