The Marlin Model 60 uses the almost universal 3/8" rimfire dovetail receiver for standard tip off rings. You will find them in a dozen or more brands, finishes and heights at just about every store in America that sells sporting goods.
Just to show you some of the brands and styles (the 3/8" dovetail versions will fit), here is Brownells
listing.
I use the Weavers on low end basic .22s, the Leupolds on my better ones, and the Talleys on my high end ones. Be sure they are for the 3/8" dovetail rimfire, as some 22s use different width dovetails. When in doubt the Weaver tip offs, the tip offs by Burris, or the Leupold tip offs are likely to be in stock at your local store.
However, they come in low, medium and high height versions, depending on how big the objective bell of your scope is. Try to stay as low as possible. Low for 20 -24 millimeter objective, medium for 40mm, and high for 50 and up.