RV Sewer Hose Carrier Gap Filler

I have an adjustable sewer hose carrier mounted under my travel trailer, like this one on Amazon. The carrier is stretched across the width of the trailer, but my existing sewer hose is much shorter than the cavity. Not wanting the stick my arm all the way into the carrier to fish out a sewer hose, I created this gap filler to stick in the other side of the carrier. This will prevent the hose from sliding to the other side of the carrier.

Diameter is approx 112mm (4.4in), height is 165mm (6.5in). Scale if needed.