If you did research as I did before tackling a DIY tread installation then you probably came across this tool. I must say it was the most important tool I needed to measure in order to get accurate cuts. The instructions suck as there are none but along with the research you did you'll figure out how to use it.On your stair thread measure the depth and cut away the excess. Use that as your measuring "rod" for this device in order to measure the width of your new tread and cut accordingly.Just to give you an idea, just YouTube the rest. A must if you want little to no gaps on your treads. There are expensive tools like this, but no need to buy those. This tool is all you need to measure.I watched the video that the merchant has posted. The poor kid is talking about how great the tool is and he doesn’t have a bloody clue what he’s doing. It works great - but you have to provide your own wood board based on the width or the stairs you’re working on. I have a 36” wide stair, so I cut a piece of oak (since it’s more stable than pine) 3/4” x 1-1/2” x 36” long to fit between the two guides. (There is a small sample piece of beech wood that is 3/4” x 1-3/8” x 4”, but you can go a little wider if you want. You can also use wood that is thinner than 3/4” without any problem.) I was just about to cut my first stair when the Amazon delivery truck pulled up in front of my house wi the the package. I’m glad he came when he did, because otherwise the cut would have been nowhere as good. This gauge allows you to easily account for the fact that the edges of your stair are very seldom perfectly square. And rather than cut it short and caulk the imperfections, this allows a tight, neat joint. Nice tool.The other brands I have seen were plastic so I was delighted when this arrived and found it is stainless steel. The measuring tape is reasonable quality too. All around it is a great value compared to the plastic versions.Super useful for every projectWas good enough to get the job done. Probably will never use again but I was able to replace a rough carpet covered stairway with oak treads and risers.Don't replace stair trends without this tool. It will make the job go much better and the results with be worth every dime you spend here.I just used this tool to install engineered vinyl plank retrofit treads on the staircase in our home and must say this is an indispensable tool. The treads came out very snug and less than 1/16" gap on either side if at all with just 1 cut on each side with a circular saw and straight edge. I wish I had bought this when I had done my basement stairs. It would have saved me sooo much time and effort.I had a little issue due to a moulding installed along the staircase that was preventing the blade from sitting flush against the stairs. I just used a hacksaw to cut off a blade about 1.5" and fixed the issue.I would love to do the risers with this too but the problem is that the 12" blades wont fit between the already I installed treads (even before I installed my retrofit treads) and the next step since that is only about 7". Would love to have a solution if someone has one other than cutting the blades to 7".The product looks durable since it is made of metal, but there are NO instructions. The seller doesn't have a video or instructions sheet on the use. I will try to find a similar product and look for online instructions or video.I purchased this because it was advertised as having the measurements engraved on the metal (which there is nothing on it). I paid more for this stair rig because of this. After a long wait to ship (even though it’s from same country) to find this out and then the hassle of returning and ordering/ waiting for another one. Since it’s just like all the other stair rigs n Amazon do yourself a favour and buy the cheaper ones save yourself shipping time and money. Do not think theres measurement marks on it as it “shows” in their advertised pictures. Also side note, the wood block s more of a guide to source one that is useful, as the one that comes with it is utterly useless unless you’re measuring stairs that are half a foot wide lol. Buy elsewhere! Absolute BS!