Is this Duro Indestro?

[rdjohannes]

This socket looks like Duro Indestro, but I’ve never seen one with simple dots on either side of the size. Duro Indestro usually has stars or trapezoids. I’ve got six 1/2”-drive sockets with similar markings. Can you help me? Thanks so much!

 

[Mintgrun]

It was made by S-K, based on the two dots.

 

[four.cycle]

^ yes. S-K. Duro-Indestro didn't have that mark.
No brand name on any of the pieces in that set.... just the dots on the sockets. Good example below:

 

[d42jeep]

The center punch marks have been an S-K indicator since the beginning. I found my first ones at an estate sale in 2017. I didn’t know they were S-K at the time
Here are some in a slide top box set.
Two early S-K sets.
Even the hex drive sockets had the dimples.
The dimple tradition continued on even into the more modern tools.
-Don

 

[rdjohannes]

Thanks so much for all the info. I live in SE Wisconsin, so lots of SK tools show up here in thrift shops and rummage sales. Also random Snap-On pieces. My latest find was a Milwaukee Tool and Forge socket!