The disc for reflected light has REF printed in white on the front. I have a couple of them. It gives a very wide angle of view, nearly useless in my opinion. Get the 5 degree or 10 degree (easier to find) viewfinder, it is put on instead of the REF disk and gives reflected readings in a narrow angle of view with a viewfinder you can use to aim it. Even though they're a lot wider than a true spotmeter, both are much more usable than the REF disk. The 10 degree goes for about $40-50 on ebay. I paid $75 for mine new back in the old days when Minolta still made meters, so the ebay price isn't bad today. The 5 degree goes for about $80 on ebay but I got lucky and snagged mine for $45!
I wonder how the 10' vf would compare the 7.5-15' attachment I have for my LunaPro SBC? It's not very accurate, in my opinion.