Two holes not 30mm apart means you need the black sheet steel queerthing which unfortunately I haven’t got a picture of for you. When you take the top off it, you need to cut the tip off the spouty bit, and for that you need a clean cut very close to the top.
Cut it too far down and the hole will be too big, your oil will go everywhere and you won’t half grumble.
IF you have a 1950 era or later TYPE 5 of TYPE 6 CASE this would be the original oil can for your machine.. Singer built many oil cans, IF you own a Canada or British machine you may/will have a different oil can with it.
We have many new 221 collectors reading our articles, I don't want to confuse them or get them in over their heads.
The red oiler was hiding in the bottom of a cabinet we bought ages ago and would be fine if it didn’t leak, as would the Perfect Pocket Oiler next to it.