Dometic Toilet Sprayer Replacement

[MilesAndSmiles]

I need to replace the sprayer on my Dometic Sealand toilet, and really don't want to pay the $50 that Dometic wants for their OEM sprayer. My problem is that I'm worried the hose diameter may be different from a sprayer I could buy at Walmart, but it's old enough that if I take it off, I may not be able to put it on again until I have the replacement on hand.

Does anyone know the hose diameter for these sprayers? Also, can I replace just the head and not the entire hose?

Thanks!