A a set of new old stock McCulloch Chainsaw muffler screws and retainer.  This fits 10- series chainsaws.

This fits the flat type muffler, if your muffler needed the three prong retainer, then the screws are likely the ones you need, if your retainer looked different these wont work.

Two have shoulder length: 3/4"

One has shoulder length: 1/2"

There were 5-6 different styles used on these saw, all of them will fit, but please make sure this is the style you want.

Check out my store for more parts your McCulloch saw.