X Teleconverter for Sigma 500mm manual focus lens (Nikon fit)?

I have manual focus telephoto lens Sigma APO 500mm for my Nikon FE.
Which 2x teleconverter you would recommend me to use with this lens?
Looking forward to hearing from you!

I'd advise you to pop into a local camera store and ask for a quick demonstration… Working at a focal length of 1000mm brings it's own problems to the table and your working aperture won't be that great either… I'm just not that keen on teleconverters, i'd avoid using them (I actually use one for macro work).

Definitely a case of 'try before you buy'… Can't go wrong that way.