[Eldest_Sibling (Alan)]

There are, generally, three types of solar-filters, and examples listed here from the cheapest to the most expensive...

White-light... https://www.ozscopes.com.au/skywatch...telescope.html

That one fits over the lens at the front of the telescope, and is the usual choice for most.

Herschel wedge... http://www.andrewscom.com.au/site-co...on-10-lunt.htm

That one fits at the back of the telescope, like a star-diagonal. Scroll down to the Lunt Herschel wedges, and in 1.25" and 2" sizes. A Herschel wedge is an enhanced form of white-light solar observing, offering a bit more sharpness, and contrast perhaps. Out of an abundance of caution however, I would use one only if the telescope is all metal, specifically the focusser, and the lens-cell(which holds and retains the doublet-lens) at the front.

H-alpha solar: https://skyandtelescope.org/observin...a092321050923/

Then, there are also telescopes that are dedicated solely to H-alpha solar observations, and are rather costly.

Then, still, there is Baader's solar-film(white-light) sold in sheets of varying sizes, and whereby you can make your own filter; for customisations.

Always practice the utmost in safety when viewing our closest star.