Plastic Test Tube Rack for 15/18 mm Tubes, Hole Diameter is 18.7mm, Holds 50, Detachable, Karter Scientific 208U2 (Pack of 1)

I got this to use for holding test tubes for my aquarium API tests. It works great. There are no instructions but basically, you just slide the racks into the little stands. The backside of the shelves have 2 little clear dots to stop from sliding too far. Once I got the first one on (the bottom rack), the others were easy. I did put a drop of cooking oil on the stand where you slide it on, as they wanted to hang up. And one I had to slide back and forth a few times until it would slide on easily. You just have to remember to put the side without the clear dots (stoopers?) in first. It's not real sturdy, but plenty enough for holding test tubes. Well worth the $6.49 I paid. It is larger than I need, but it will make the process so much easier. I guess if you wanted it a little more sturdy you could put a drop of glue on the stands. But not necessary at all. They hold well, even when carrying empty. I wouldn't carry it full of test tubes.

Works great. Love it. Good price.

These are perfect for chocolate dipped pretzels! They are durable, easy to assemble and easy to clean.

I bought this test tube rack for holding ink samples from Goulet Pen's Ink Drop program. I like that it holds 50 samples instead of the 40 that Goulet's model holds, and honestly, I'd have to guess that the same manufacturer makes both models. Because there are five rows per column and because each drop contains five samples, too, it's super easy with this rack to organize your samples by month. I love that!Some criticisms of this model claim that it falls apart easily if you try to move it, but I've found that that's not really the case for me, especially if there are tubes in any of the slots. Because the tubes actually go through the holes in the first and second layers, a tube acts as a sort of "pin" holding both layers together. The fit of each layer into the slots of its holders, too, is quite snug and not likely to come loose. I can pick my model up and wave it around all day long without it coming apart. However, if your fittings are lose, a small tab of glue on the open ends of each slot can lock the inserts into place permanently. For the price, I find just a wee bit of DIY totally acceptable for using this thing to its fullest potential, but hey--for $6, I'm happy the thing will just sit still on my desk without falling apart. Plus it looks nice.I do wish the manufacturer would include slots on the top of each side holder and pegs on the bottom, placing them so they interlock if stacked. I think there's actually enough clearance on the bottom of this unit that I could stack them on top of my ink samples, if only the one on top could be secured so it doesn't slide around. And the quality control on these clearly isn't all that great. My unit arrived with a tiny crack in the bottom shelf and slight irregularities in the slits that made assembling the thing a little tricky. Had it gone the opposite way, with irregularities that made the thing too loose instead of too tight, I can see how that could let the shelves slide out too easily. Again, though--$6.All in all, a wonderful solution for storing sample ink vials. I like it and would recommend it especially to those who keep lots of samples on hand or are subscribers to the Ink Drop program.

I used itto take daffodils to a flower show, itworked wonderfully.

TO HOLD BLOOD SPECIMEN TUBES! EXCELLENT!

Well, first off, the color of this product is a very bright, transparent, light teal color. I actually love the color much better than their picture's plain transparent blue. But it's just surprising to receive something that looks totally different than what you expected.I had trouble trying to slide the individual pieces in and had to get some help after 15 minutes of failure. It wasn't super simple to figure out, because the racks only fit in a certain way....but maybe it will be easier for others.Once it was all put together, it seemed ok.The rack holds up my lip balm containers, although it's all pretty flimsy.The thin plastic trays bend up or down very easily with any kind of pressure. I have little doubt that eventually it will break or snap somewhere. This is not stiff or thick or layered plastic at all.But for $6 or $7, it's not too bad. If the price was up above $10, that would be extreme overpricing.I'm a bit disappointed that it holds so few tubes. It just seemed like more in the picture, but I'm sure that's just my bad for not realizing the true size.I put lip balm tubes in several of the rows.. then I placed a few empty 5-10ml round lip balm jars on the extra space on top. But it doesn't stay put well. If I touch the rack, things instantly fall off. This is the cheapest you can go, in terms of plastic durability. A very small child could probably break each rack by himself, without intense pressure.So. This is just ok. But what can you expect for $6 other than a few slices of plastic with holes in them?This will still do its job properly, so no major complaints yet. I had just expected something more solid at the least.But. I DO like the pretty color.... so that's a plus... right?

These are 1/3 of the price of those from my favorite pen & ink supplier, and they're better: these have a bottom layer that makes it possible to lift and move this rack while vials are still open. The pen supplier's rack has dumped out uncapped vials I was working from, because I needed to move the tray and didn't remember this flaw. I've got a few of these now, and they're sturdy. Not furniture sturdy, but I caught myself leaning on one and it didn't break. Not advisable, but good to know. They do flex a bit, but no mishaps.Be sure to align the 3 layers correctly and smooth side up before installing. The layer with small holes goes at the bottom. You can only install them from one side.