This is an excellent question. The characteristics for Pounce and STS are similar because the products are targeting species of fish that spend their time in environments that have some very similar characteristics like rocks, weeds and wood.
For that reason, both offer exceptional abrasion resistance and strength and deliver all the other benefits of fluorocarbon like fast sink rate, low stretch and invisibility.
Diameters for most Seaguar lines are the same for the lb test sizes as they are all built to conform to the proper break strength. There are a few exceptions in line diameter sizes but not many. Both Pounce and STS are made from 100% Seaguar fluorocarbon resins.
Unlike STS, Pounce is targeting bass anglers - both the casual weekend angler and those that fish local tournaments. Also, Pounce is on 25 yard spools to help keep the price affordable and enable anglers to buy several spools of different lb. test sizes to meet different application needs. Lastly but important, Pounce is merchandised in a box instead of the typical “Leader Ring”. Hopefully this adds a little familiarity to bass anglers who are not always used to seeing leader spools on retail displays.