Recently I bought a Skywatcher ST80 refractor to use as a finder on a 10" GSO Dob. The focuser of the ST80 accepts only 1.25" diagonals and is of the R&P type.
I immediately replaced the stock focuser with a GSO crayford focuser which accepts 2" diagonals, i.e. 2" eyepieces and larger field of view.
The original R&P focuser is offered for sale.
Asking price $40.00 which includes registered post anywhere in Australia via Australia Post.