Where do I start, accuracy? It isn't. Check the photos for my evaluation. In the straight-locked position, it is neither square nor accurate in measuring. It is about 3/32 off on the measurement and is .2 degrees off; after pulling it as far as possible while still locked, it naturally sat at about .5 degrees off. Forget about getting any angle to be precise, there is too much slop and no index to lock it into position. You could use an angle gauge to get it there, but that defeats the point. The holes in the marking guides are deep and big. My scribe has a lot of slop inside the hole, and a mechanical pencil has no hope of not breaking due to how far you need to extend the lead. Find something else if you're trying to make anything with any accuracy.

This adjustable t square is fairly well made, comparable to other measuring and layout tools that I own. It can be used as a square, with a fixed lock at 90 degrees, or as an angle ruler with several angle markings. It can also be used as a protractor/triangle to copy an existing angle onto flat material, although it won't work well on inside angles such as inside cabinets. The drilling guide feature is OK. The guides have 2 hole sizes, one for 5mm cabinet knob screws and one smaller. The drawback is that compared to a normal cabinet hardware drilling template, this product is harder to align and center measurements so that multiple cabinets match. It does work well for other cabinet building applications like drawer glides and shelf supports. Nicely finished and comes with a well made carrying/storage case. It's not the perfect tool, but it does fit into a big tool bag where a rafter square won't. Recommended with slight reservations.

Never had anything like this before in my shop. Quality and precise measurements along with a sturdy travle pouch to protect this instrument makes it a winner. It measures up

This very well-made T-square is going to see a lot of use in my shop. It's made from two pieces of sturdy aluminum plate, joined together by a tightening knob. There is a hard detent at 90 degrees and easy to use markings for 30, 45, 60, 75 degrees. There are four sliders for marking or drilling, with two holes each for marking pen, awl or drill. Comes with a nice carrying case. I wish I'd had this years ago - it's a definite step up from a standard T-square.

I haven’t yet figured out all the ways I’ll be able to use this ruler in my workshop, but I’ll be very glad to have it when the need arises. It’s made of nice sturdy, aluminum, and the moving parts have nice tight tolerances. This style of sliding t-square is very practical for measuring and marking both lengths anbd angles or anything up to 24 inches. It has indicators for commonly used angles, and a detent that holds the arms at precisely 90°. The 24-inch size makes it useful for fairly sizable projects without being so large that it’s unwieldy. The drill/pencil guides are very useful for ensuring consistent, markups and hole drilling for applications, such as cabinet doors. The built-in spirit levels are very convenient. My only complaint is that there’s no metric scale on this ruler. While I don’t use metric measurements all the time, sometimes it’s very handy to use in place of imperial. I think this ruler misses an opportunity by not having metric measurements included. However, this is a very small matter that doesn’t distract from this t-square’s overall excellence. I can confidently give it five stars.

I've been using my dad's old square (it's so rusty it is hard to see the markings). This adjustable square will replace the antique (I will clean the old one up and put on display in my shop). Not only is this a t-square, you can set the cross bar to several pre-marked angles. There are detents in the cross bar for 90° (so you're absolutely sure it is square). The cross bar can be set at any point along the center slot of one side of the ruler by using the knob. The cross bar can be relocated to the opposite center slot. The center slots also hold 4 scribe/drill hole shuttles. The shuttles can be located in the slot on either end of the ruler. The two holes in each shuttle are 3mm and 4.5mm. The ruler has two bubble levels (vertical and horizontal). The markings on the ruler and cross bar are in 1/8" increments (one 6 1/2" edge of the cross bar is in 1/16" increments. On the ruler, the markings go up from left to right on one edge and right to left on the other. The cross bar has plastic inserts in each end that have 3/8" tabs that allow the these tabs to sit on the horizontal surface of the material being measured (with the cross bar on the vertical surface), stabilizing the t-square. These plastic inserts are not secure, which is not an issue until you hang the t-square using the nail hole in one end. The plastic insert may come out, causing the t-square to fall. A little glue should remedy the situation. After the inserts are taken care of, this t-square will be an real asset in future projects. When the cross bar is aligned with the ruler, the t-square is easy to carry in the included case. I detected no visual or operational defects in manufacturing.