Heathrow Scientific HS29022G Interlocking 4 Way Tube Rack, Polypropylene, Assorted Colors (Blue, Green, Pink, Yellow, Orange), Pack of 5

Whether is 500ul, 1.5ml, 15ml or 50ml tubes, this classic and nostalgic tube racks will easily have you covered. It is the most overused tube rack in my laboratory and I have a lot of these. It seems that no matter how many of these we have, they almost always all get used up during the entire working day of experiments.Each side of the tube rack has different-size holes to account for your specific needs in sample preparations. I have overused these tubes during my PhD and continue to use them afterwards and it really captures the nostalgic feel while also being very helpful.It can be use for O-ring tubes in the side that holds 1.5ml eppendorf (or any 1.5ml) tubes. I have used these for western blot where it holds the O-ring prestained ladders from Biorad and works perfectly alongside my samples. I have also used it for cryogenic vials with O-ring tubes (although for cryogenics vials, I would maybe use another type of rack since those O-ring screw caps comes in a variety of volumes and some may exceed the classic 1.5ml volume). Depending on the cryogenic vial that you have, it may or may not fall right through. In my case, it tends to hold in place but test it out first before going to place it on this rack.Finally, one small rant that I have for this tube rack (but not enough to lower its star rating since I am used to it) is that whenever you are using 15ml tubes, have in mind that its lower bottom will fall right through the section of 50ml tubes. Since the hole of 50ml tubes is much larger than the 15ml, the bottom tip of the tube it will easily fall through slightly BUT it will stay in place due to its screw cap. Trust me, it will stay in place but it will wobble a lot when moving the test tubes. It is slightly annoying when you have a lot of samples in 15ml tubes and you need to be very careful for any type of sudden motion (such as a cell sediment pellet in the cell supernatant).You can also freeze your sample at -80℃ with these test tubes (as shown in the attached image).

Versatile, value with color coded, bench space saving

as advertised. These do a good job especially for holding microcentrifuge tubes. Not so good for 15 or 50 ml tubes, but they will work in a pinch.

Great colors. They didn't fit well together.

Decent tube racks for my classroom that hold various sizes of tubes. It makes storage so much easier with little space available.

Very nice and effecient to hold 20 of 50ml centrifuge tubes.They are 5 racks: blue, yellow, pink orange, and green.

Priced right for what one receives. Not the best syringe holder, but the bet one for the $$$$.

I ordered these to use with my high school students, and they are totally impractical for test tubes. I was looking for something that could be easily washed and stored and would fit in our small budget, and thought these would work well. If students put their 15 ml tubes in the rack and picked it up, the tubes will fall through the larger holes on the opposite side. I thought I solved this by flipping the racks over and using tubes slightly larger than the holes on the bottom side so they couldn't fall through. This limited students to running only four samples at a time. When the students were actually using the racks this way, some of the tubes still broke because they were so much smaller than the holes on the top that they were able to slide out of the rack diagonally when students were carrying them back to their seats.The structure also makes it impossible to see the solutions in the tubes while they are in the rack, so when students needed to compare the color of the solution in each tube, they had to take turns holding the tubes for each other so they could record their observations. These racks probably work fine with conical tubes that have a lid, but are unusable as it for regular test tubes. I've added a plastic panel to one side of the racks so that students can use them without the test tubes falling through (hopefully).