The screw-in type mirrors are usually fitted to bikes without fairings. There are two size being 8mm or 10mm thread fitting with a standard right hand thread (Clockwise). However, Yamaha uses a right hand thread on the left and a left hand (Anti-clockwise) thread on the right but again these will be 8mm or 10mm. There's also one or 3 later Honda models that have a similar set-up to Yamaha so be careful when buying replacement mirrors. If you're replacing fairing mirrors, check that the fixing mount hole centres in the description match your originals and also check that the image is a good enough likeness.