These are quality countersink bits that are made in the USA. The bits are of a reasonable quality for these tools since they are only needed for the pilot hole to guide the countersink. I use the bits that ship with these tools until they dull then switch them out with titanium or cobalt bits. It's the countersink that is the important part of the tool and they cut clean without chipping & splintering the wood. I use a hone to lightly dress the cutting edges to prolong the tool life. They can be used with a quick release adapter or in the drill chuck itself. These are a great bargain especially when on sale.
First off, if you ever see any tools on sale at Sears then you must pay for it on line to get that price. You can't go to the store to get the same price. It doesn't work that way. I don't know any other company that does this! I didn't know until I bought these countersinks. The drill bits are of poor quality. The countersink part will tear up soft wood if you don't clean out the scoop each time you drill. I learned the hard the way. Used it a few times and the drill bit broke IN THE FURNITURE I WAS MAKING WITH NO WAY TO GET OUT!
These countersink combo-drill bits are great for woodwork projects requiring flush screws. I was a little apprehensive about the drill bit being held by a hex grub screw but it means the drill depth and therefore screw depth are adjustable and it works well. Good addition to the toolbox!
Very easy to use and change over. If you do wordwoorking this is for you. I have even used these on my drillpress